The action of binocular cells in visual cortex is the foundation of information process of stereopsis. The disparity encode mechanism of simple cells are divided into two groups, one is position shift, the other is phase shift, but simple cells are not suited to act as disparity detector. On physiological study of some complex cells, people find some complex cells are ideally suited as disparity detector. A complex cell energy model based on these simple cells was provided. Mathematical analysis and computer simulation indicate that this model can explain many physiological data.