Abstract: In this study,soybean lecithin was used as a surfactant to study the effects of surfactant content,ultrasonic power,ultrasonic time and interaction on the average particle size of ultrasonically prepared green tea seed oil and fractionated coconut oil nanoemulsion. The response surface preparation method was used to optimize the preparation conditions and evaluated the stability and in vitro digestion of the nanoemulsion was analyzed. The results showed that the optimum process parameters were:Surfactant content 2.2%,ultrasonic power 351 W,ultrasonic time 12 min,and the average particle size of the obtained nanoemulsion was(183.00±1.58) nm. The soy lecithin-stabilized nanoemulsion had good stability with pH6~8,heat treatment and storage. The nanoemulsion system was significantly improved with the in vitro digestibility of green tea seed oil and fractionated coconut oil,and the free fatty acid release rate finally reached 87%.