The schizophrenia is affected by the genetic factors, natural environmental factors, psychological stress factors and many other factors. However, most studies only focus on one of them, and few hypothesis can give attention to multi-factors. Therefore, the viewpoint of Darwinian medicine and evolutionary psychology was adopted to analyze the schizophrenia in order to speculate the cause of schizophrenia, and explain how the genetic factors and the natural environmental factors affect the schizophrenia. On this basis, the characteristics of the onset of the schizophrenia was analyzed, and a new theory on the cause of the schizophrenia was putting forward and demonstrating: the related genes of schizophrenia was a group of genes replying for the adverse environment, under the feedback control of the environmental factors. When the environment was bad, the over expression of the genes cause the schizophrenia.