Mormonism differs from Orthodox Christianity on the Doctrine of the Holy Trinity, but how does it differ? From the horse’s mouth, I mean the Prophet Joesph Smith’s mouth:
Sermon by the Prophet—The Christian Godhead—Plurality of Gods.
Meeting in the Grove, east of the Temple, June 16, 1844.
“I have always declared God to be a distinct personage, Jesus Christ a separate and distinct personage from God the Father, and that the Holy Ghost was a distinct personage and a Spirit, and these three constitute three distinct personages and three Gods. If this is in accordance with the New Testament, lo and behold! we have three Gods anyhow, and they are plural: and who can contradict it?”
“Many men say there is one God; the Father, the Son and the Holy Ghost are only one God! I say that is a strange God anyhow—three in one, and one in three! It is a curious organization.”
“John was one of the men, and apostles declare they were made kings and priests unto God, the Father of our Lord Jesus Christ. It reads just so in the Revelation. Hence, the doctrine of a plurality of Gods is as prominent in the Bible as any other doctrine. It is all over the face of the Bible. It stands beyond the power of controversy. A wayfaring man, though a fool, need not err therein.”
“In the very beginning the Bible shows there is a plurality of Gods beyond the power of refutation. It is a great subject I am dwelling on. The word Eloheim ought to be in the plural all the way through—Gods. The heads of the Gods appointed one God for us; and when you take [that] view of the subject, it sets one free to see all the beauty, holiness and perfection of the Gods. All I want is to get the simple, naked truth, and the whole truth.”
There you have it from Joseph Smith’s own mouth, there is a plurality of Gods. He denies that Doctrine of the Trinity, that God exists in three persons with one divine substance, or essence.
Here is the link to the sermon: http://byustudies2.byu.edu/hc/6/24.html
From Good Ole Brigham Young University.