Two-dimensional simulation in Plasma Enhanced Chemical Vapor Deposition (PECVD) is conducted by using multi-physics analysis method. Simulation results show the growth process of amorphous silicon thin film in the PECVD reactor. The effect of process parameters (such as power supply power, electrode spacing, etc.) on the deposition rate and electric field strength is obtained, and the optimum conditions needed for growth of amorphous silicon thin film is achieved as well. It was experimentally proved that the simulation results are consistent with the experimental results, and provide a theoretical basis for adjusting and optimizing the film preparation process.