Abstract: Preparation technology of microcapsules of fish oil from Decapterus maruadsi was investigated by spray drying through the experiment of single factor and response surface optimization research, the microstructure and stability of microcapsules were also determined.The effects of fish oill content, solid concentration, inlet and outlet air temperature and feed rate on the microencapsulation efficiency of fish oil were studied. The results showed that the optimum conditions for the spray drying preparation of fish oil microcapsules of Decapterus maruadsi were as follows: core material content 30%, solid concentration 37%, inlet ( outlet) air temperature 190 ℃ ( 85 ℃) , feed speed 480 mL/h. Under the above optimal conditions, the microencapsulation rate amounted to 91.56%.The fish oil microcapsules that prepared was spherical in shape, smooth in surface and compact without cracks.After accelerating oxidation under 60 ℃ of 6 days, POV of Decapterus maruadsi microcapsule was significantly lower than non microencapsulated fish oil ( p < 0.05) . The stability of Decapterus maruadsi fish oil significantly increased in microcapsule ( p < 0.05) .