Abstract: The effects of polysodium p-styrene sulfonate（PSS）on wide-bandgap perovskite films and devices are studied in this paper.The research of this paper shows that use of a polypodium PSS passivator can effectively improve the morphology,increase the crystallinity,and reduce the defect density of perovskite films,which are beneficial to inhibit the phase segregation of mixed-halide wide-bandgap perovskite films. Finally,the J-V test results show that the performance of the optimized wide-bandgap perovskite solar cell is significantly improved. In the wide bandgap perovskite solar cell with PSS,the open circuit voltage is up to 1.23 V,and the efficiency is up to 20.54%. Moreover,the stability of the encapsulated device is significantly improved after phase segregation being inhibited,and the efficiency remains 81.9% of the initial efficiency under continuous illumination for 500 h（N2environment,40 ℃）.