With grass carp fish oil as core material, soybean protein isolate and chitosan as composite wall material, fish oil microcapsules were prepared by ultrasonic assisted homogenization and spray drying. In order to determine the release performance of core materials under different storage temperature, relative humidity and light intensity, the release kinetics of microcapsules under different storage conditions were investigated. The results indicated that release kinetic equations were significant and credible, with R² greater than 0.97. Moreover, the release mechanism parameters were fouls less than 1 under theconditions of 4~50 ℃ and 34% relative humidity, which belonged to the diffusion-limited kinetics andfirst grade release. When the relative humidity was 54%~92%, the light intensity was 0~10 000 lx, and the release mechanism parameters were all greater than 1, which belonged to the first-order release kinetics. This indicated that the fish oil microcapsules could be better preserved at low temperature, drying and avoiding light. The particle size decreased from 15.82 μm to 2.98 μm after 270 min, and the release rate reached 80.6%, indicating that the microcapsule had sustained release behavior in the simulated digestive tract.