We have calculated the electronic structure and optical properties of zinc blende structure ZnSe under different high pressure by means of plane wave pseudo-potential method (PWP) with generalized gradient approximation (GGA) in this paper. The total energy, density of state, energy band structure, and optical absorption and reflection properties under high pressure are calculated. Furthermore, we analyzed the change of electron structure, band structure and optical properties under high pressure using the results of experiment and theory.