The theme of Alice Walker’s The Color Purple is very straightforward and simple. Like many other novels devoted to the mistreatment of blacks and black women especially, The Color Purple is dedicated to black women’s rights.
Much of the narrative in Walker’s novel is derived from her own personal experience, growing up in the rural South as an uneducated and abused child. In short, the goal of this book and indeed all her writing is to inspire and motivate black women to stand up for their rights. Celie, the main character, undergoes an inner transformation, from a submissive, abused wife to an unabashedly confident and independent black woman and businesswoman.
There are other more secondary themes, such as the rejection of the traditional, Christian, "white-man's" God. Thanks to the influence of Shug Avery and Nettie, a new age kind of God is developed and is a great comfort to all three women. Even Celie's last letter is written to this vague kind of god-- a god of nature and stars and people.