The quality of a perovskite film will directly determine the performance and stability of the corresponding perovskite solar cell. High-quality and uniform CH3NH3PbI3 films were synthesized by a new hybrid physical-chemical vapor deposition (HPCVD) process in a vacuum and isothermal environment. The reaction temperature can be accurately adjusted from 73 °C to 100 °C, with 73 °C as the lowest reaction temperature for a vapor based approach. CH3NH3PbI3 solar cells with high performance were fabricated at 82 °C to achieve a high power conversion efficiency (PCE) up to 14.7%. The unsealed champion solar cell was tested for 31 days continuously, and its efficiency could maintain 12.1%, demonstrating high effectiveness of this HPCVD process.