Organic-inorganic hybrid perovskites are key materials for high efficiency solid-state solar cells.Different halide elements in perovskite show diverse properties.Basing on a stability crystal structure of organic-inorganic hybrid perovskite CH3NH3PbI3,we established different Cl doped CH3NH3PbI3-xClx crystal structures and calculated geometric structures,electronic structures and optical properties of them by first-principles calculation using the CASTEP module in Materials Studio respectively.We found that the calculation results of X-ray diffusion patterns were reasonably consistent with our experimental results.We also indicated that the photoelectric performance of CH3NH3PbI3-xClx system was superior to that of CH3NH3PbX3 system.Besides,the largest carrier concentration and the relatively smaller band gap made CH3NH3PbI2Cl perovskite crystal structure more suitable as the light absorption layer of solar cells.