All-inorganic perovskite solar cells require high-temperature preparation processes, which severely hinders their further commercial development. Inorganic perovskite materials have a high crystallization barrier, so the crystallinity is poor under low temperature conditions, resulting in poor device performance. Therefore, it is an important challenge to develop an excellent low-temperature preparation process. In this paper, the crystallization kinetics of the CsPbI2Br perovskite film under low temperature conditions was studied, and it was found that the perovskite was not completely crystallized during low temperature crystallization, and PbI2 remained. The PbI2 residue not only caused the appearance of lead defects but also formed insoluble CsBr due to the insufficient reaction of the raw materials. Through the interaction between the organic molecules 3-Amino-3-(3-pyridyl)propionic Acid (PA) and PbI2, the crystallization reaction process can be effectively improved. Eliminating the residual PbI2 also effectively inhibited the precipitation of CsBr, thereby significantly improved the crystallinity of CsPbI2Br. Efficiencies of 10.95% are achieved for low-temperature-processed CsPbI2Br planar-architecture FTO/SnO2/CsPbI2Br/carbon, and the obtained device also showed good stability in the air.