Abstract: Walnut oil is rich in unsaturated fatty acids. To avoid the oxidation and broaden the use of walnut oil, walnut oil microcapsule was produced by spray drying method using modified konjac gum as main wall materials. Box-Behnken mode of response surface methodology was applied to optimize the formula of products.Then the shelf- life, microstructure of microencapsulated walnut oil were evaluated. The results showed that the optimal formula of the walnut oil microcapsule was walnut oil 34.9% , modified konjac gum 29.1% , soybean protein isolate 18.2% , maltodextrin 16.8% , glycerin monostearate 1% , and the microencapsulation efficiency could reach 90.48% under optimal conditions.The microcapsules containing walnut oil were particles of spherical shape with no crack and no hole on the surface.The particle size showed uniform.Moreover, the shelf-life of walnut oil was prolonged.