Abstract: In this paper,the combined effect of heating and water processing on the control of PbI₂ film morphology and its influence on the performance of perovskite solar cells are studied. The perovskite system used is（FAPbI3）1-x（MAPbBr3）x,and the PbI₂ film can be prepared into a porous structure by heating the PbI₂ film for different times and short-time water processing on the basis of a two-step method. The quality of the perovskite film prepared by the dual-processing is significantly improved,which is manifested in the obvious increase in the grain size of the perovskite,enhanced crystallinity,increased light absorption and faster carrier transport. And this method can effectively control the residual amount of PbI₂ in the perovskite film. The open-circuit voltage,short-circuit current,fill factor and efficiency of the cell prepared by heated PbI₂ film are 1.05 V,23.12 mA/cm~2,73.81% and 17.92%,respectively. These four corresponding parameters of the cell prepared under the optimal dual processing are 1.09 V,24.75 mA/cm2,77.85% and 21.10%,respectively.