Photochromic microcapsules with polymethyl methacrylate as the shell material and spiropyran photochromic dyes as the core material were prepared by solvent evaporation method. FTIR, SEM, particle size analyzer, spectrophotometer, and colorimeter were used to characterize the micro-morphology, particle size, and color of the microcapsules. The results show that the core-shell mass ratio (core / shell) has a significant effect on the morphology and performance of the microcapsules. When the core-shell mass ratio is 2: 1, the microcapsules have good color performance, and the △ECMC before and after color change is 20, and the microcapsules have a strict surface and a smooth surface. When the core shell mass ratio is larger than 2: 1, the microcapsules cannot be coated well. The photochromic microcapsules immediately change color when exposed to ultraviolet light, and the complete discoloration time is 16s. After 30 cycles of UV-visible light, it still present excellent photochromic sensitivity.