who is the main character?

Uncle Tom can, at some point, be considered the main character. He is the eponymous character (the one whose name is used in the title), and it is his name and his behavior that have come into our vocabulary with a negative connotation. His servile behavior in front of all the white characters is, for him, a kind of survival behavior, yet many now see that behavior as too fawning and thus insulting.

I think that main character in Uncle Tom's Cabin is Uncle Tom. I think this because the book is somewhat a story of his life.