The microemulsion of coconut oil was prepared with span 80 and Tween 80.The effect of preparation method,hydrophilic lipophilic balance value (HLB),cosurfactant and emulsifier amount were investigated for determining the best process parameters of coconut oil microemulsion.The results showed that stable oil in water microemulsion of coconut oil can be prepared by ultrasonic assisted stirring method with HLB12,glycerol as cosurfactant and 3.2％ of emulsifier.The microemulsion had the best stability when the ratio of total amount of coconut oil and emulsifier and the amount of water was 1 ∶ 9 or 2∶ 8,the microemulsion was not stable at low temperature when the ratio was 3∶7.