The Bible alone is their only spiritual authority.

God’s Grace alone saves us, through the sacrifice of Jesus Christ.

Faith alone is the only requirement for God’s acceptance.

Where did Presbyterians come from? 
Presbyterian is the Scottish name for the “Reformed” branch of Protestantism. The Reformed movment began in Geneva, Switzerland with the teachings of John Calvin.  It soon spread to many countries, including Holland, France and England.  John Knox, who studied under Calvin, is credited with bringing Reformed belief and worship ti Scotland.  The name “Presbyterian” refers to the way we govern our churches, through elders and councils.
What makes Presbyterian churches different?
Reformed churches emphasize the Bible and Bible study.  While they recognizing the strengths of other branches of Christiansiy,  Presbyterian-Reformed Christians  believe all practices in the church are governed solely by Biblical truth, interpreted through rational, prayerful study.  They place a high emphasis on education and on free discussion and debate.
The most distinctive doctrines of Presbyterian church are the Lordship or “sovereignty” of God,  the sinfulness or “depravity” of people,  predestination of all things,  a universal approach to God’s calling, and a balanced approach to church government.
What do these distinctives mean?
1. Sovereignty--God is king!
All Christians believe that God is Lord. What makes Reformed Christians differ from others is how far they take it.  Presbyterian-Reformed people believe that God is absolute Lord over everything We believe that in Him all things “live and mover and have our being.” God is not just a “general manager” of creation.  He is involved in all the minutiae as well.  God literally knows and cares about every hair on your head, every blade of grass, and every flower in a field.  God takes an active interest in everything that happens in His universe.
2. Depravity--people are broken! All Christians believe that people are sinful.  “All have sinned and fall short of God’s glory.” Romans 3:23.  Again, what makes Reformed Christians different is the degree to which they take it.  Reformed Christians believe that not only everyone, but every part of every one is affected by sin.  “in Adam’s fall, we sinned all.” We are all affected by sin in our bodies, our emotions, our reasoning, and our will, so that no part of our nature may fully be trusted.  Left fo our own devices, our sinful nature will pull us inevitably to the bad side.
3.  Predestination--God is in control.
Predestination is the most controversial part of Presbyterian teaching.  It is, however, the logical outcome of believing in Sovereignty and Depravity.  We cannot save ourselves, neither can we trust that people will ever choose the good if left to themselves. Presbyterians believe that God has to create faith in us in order for us to choose Him.  Faith in God is a gift given to us by the Holy Spirit. Once that faith has been given, a person is called to Christ.  They will come to Him according to John 6. 
So why does God create this faith in some , and not in others.  We do not know. It is a mystery only God knows. But then, Presbyterians allow that we don’t understand everything there is about God and His will.
4. Calling--Everyone is important
Another aspect of God’s sovereignty is His interest in all things.  In pre Calvin days,  the church believed that God called people to religious vocations such as priest or nun, but not to other things.  Serving God in a church profession was considered the highest calling of all people.
Reformed Christians do not accept that the secular world is any less important to Him than the sacred world. God not only called people to be ministers.  He also called them to be plumbers, politicians, and school bus drivers.  God is interested in every aspced of the human condition, and calls us all to serve Him wherever we are.  This is the origin of the word “vocation.”
This led to a revolution of thinking in the Western world.  Reformed teaching elevated artists, politicians, and businessmen to see their work as being a legitimate way to serve God.  This led to changes in art, business, and politics.  Ordinary people were challenged to live out their faith in everyday life, in a way that they never were before Reformed Christians.
  5.  Government—Rules are good
Because God is king, then government must also exist in heaven. Governement is good.  Because people are sinners, no one person can be trusted to hold the reins of human government.  Presbyterians believes that people should be governed by councils of called people, chosen by their constituents, goverened by the rule of law, and answerable and accountable to those they govern.
Sound familiar?  It should. Presbyterian church government provided the pattern for the Unites States government, with its checks  balances and layers.  The first governmental document in America—the Mayflower Compac--,was drafted by Reformed Christians Throughout the world, the Presbyterian ideas of government has been an inspiration for modern democratic and constitutional movements. 
I heard that Presbyterians supported gay marriage, universal salvation, didn't believe in the Bible, etc. Is that true?
We are not those Presbyterians! While it is true that some churches which call themselves Presbyterians do believe and practice such things, we are not in any way affiliated with them, neither do they follow the historic teachings of the founders of the Presbyterian Church. Our denomination believes that the Bible is without any error, that marriage is between a man and a woman, that the only way to salvation is through Jesus, and that the Bible alone is our only rule of faith and practice. This was the historic teaching of our Presbyterian fathers, and it is our practice now.
How is the Presbyterian Church governed?
Presbyterian churches choose elders from each congregation.  These elders meet in Presbyteries,  or councils of elders, to settle matters of the church.  Presbyteries also ordain ministers, who become members of Presbyteries.   Presbyteries form Synods, and Synods form General Assemblies.  No one layer of government has all authority.  Every layer must answer to those above and below them.
What do Presbyterians believe about Baptism?Since salvation is an act of God alone, they do not believe baptism saves people.  Instead, it is an act which symbolizes a person’s belonging to Christ’s family and kingdom.  Because it is only a symbol,  then is may be done in a variedy of ways—sprinkling, pouring, or immersing.  Presbyterians believe that children are also part of the kingdom.  As Jesus said “Suffer the children to come to me.” For that reason, they also baptize the children of believers.
What do Presbyterians believe about the Lord's Supper?
Presbyterians believe the the Lord’s Supper, or Communion is a symbol given by Jesus of our place in His family.  Since it is just a symbol, the lord’s supper does not save us. Presbyteriena believe that the Lord’s super symbolized not only our unity with Christ, but also our unity with other believers.
Where can I learn more about what Presbyterians believe?
The Westminster Confession of Faith and the Catechisms, best explain the beliefs of the Presbyterian Church. Click Here to see them.