The solution processible CH3NH3PbI3 perovskite film possessing efficient power conversion efficiency has received considerable attention for cost-effective solar cells. However, the large difference in solubility between PbI2 and CH3NH3I is problematic to construct uniform perovskite film creating pin-holes due to the incompatible crystallization rate. Here we investigated the optimization of the DMSO addition process to reduce pin-holes on perovskite film.