The photochromic microcapsule with narrow particle size distribution and smaller average particle size was prepared by emulsification-chemical crosslinking method utilizing spiropyran photochromic dye as core material and chitosan as shell material.The effects of emulsifier types, ultrasonic time and core-shell mass ratio on the particle size of microcapsule were investigated. The thermal stability and photochromic properties of photochromic chitosan microcapsule were studied. The results showed that the particle size distribution was narrow and the average particle size was 3.2 μm when the emulsifier was Tween80 and the mass fraction was 5% in the aqueous solution, the ultrasonic time was 2 h and the core-shell mass ratio was 1:3. The microcapsules prepared under these conditions were able to withstand the high temperature about 300 °C.The times of photochromic microcapsule dispersion to achieve color and fade steady state were 4.25 s and 26.00 s, respectively. The time of photochromic microcapsule dispersion to achieve color and fade steady state was only 0.25 s and 4.00 s higher than that of the photochromic dye dispersions. Moreover, the photochromic microcapsule had good photochromic reversibility.