The present article tries to study the power and knowledge in the novel “the color purple written by Alice walker from the perspective of post modernism”. In this novel, different elements of post modernism have been restricted to the issues of knowledge and power. The novel “the color purple” is of some features describing it as a post modernist work. Have in, when the characters experience life, they have a relative understanding of it, but when they try to understand the life, they really experience the life. They experience the life through a special knowledge. This knowledge forms a great part of the discourse created by power and power relations. There is no knowledge without power and relevant institutes. In such a society power is an important factor, a source for oppressions, and, at the same time, it has some advantages for some people in the society. Finally, the characters be have strangely, in other words, they suffer from the lack of relation with others. In fact, the characters communicate with each other, but it is not understandable for the others, since the people are merged in to a discoursal network. Discourses differ in different places because people have different attitudes toward life and every thing makes no sense in such a society.