Abstract: Organic-inorganic hybrid perovskite solar cells are currently a research hotspot in the field of solar energy, among which the additive engineering is one of the very promising strategies to control the crystal defects and improve the perovskite solar cell performance. Chlorine-based additives are among the most common additives found in the literature. In this work, the effect of adding methylammonium chloride （MACl） on inverted wide-bandgap perovskite films and the cell performance was systematically studied. The research results of scanning electron microscopy, atomic force microscopy, X-ray diffractometer, and time-resolved fluorescence spectroscopy showed that the addition of MACl had no significant effect on the thickness of the perovskite film, but could change the grain size of the perovskite films and the roughness of the film surface. The crystallization state of the perovskite film was significantly affected by the MACl concentration, and the MACl can inhibit the growth of the secondary phases. Insufficient or excessive MACl concentration was not conducive to the crystal growth of the perovskite film. By precisely controlling the amount of MACl added, a perovskite film with good crystallization state can be obtained, which effectively improved the carrier lifetime of the perovskite film and significantly improved the electrical performance of the cell. The efficiency of the optimized inverted wide-bandgap perovskite cell was 18.45%, and all the performance indicators were significantly improved. The above results indicate that MACl is an additive material that promotes high-quality perovskite film formation and achieves high-performance devices, providing great opportunities for perovskite cells to move towards practical applications.