Aimed at the problem of litchi drying performance is restricted by its shell pore structure, each side of the shell pore shape was observed by electron microscopy and its average porosity was calculated by Image-Pro software. Through building a model of water evaporation at high temperature, heat and mass transfer coupling for litchi multi-layer structure, using the Fluent software to simulate the temporal variations of temperature, pressure and velocity in litchi drying process, the difference between simulation result of water volume fraction in this process and experimental value was compared. The results show that the pore structure exists a self similarity in each surface of litchi shell, average porosity is 0.516±0.032; when litchi is dehydrated at 70℃, temperature of the fruit body conducts from shell towards its interior and reaches the equilibrium state gradually; a negative pressure is gradually increasing on its inner surface; water vapor on the flesh surface is with low velocity and small pressure difference, but with the time increase of loss water, the fluctuation of vapor velocity and differential pressure increase too. It’s showed that the simulation result can be better corresponded with the experimental value. These research results would provide a reference for other multi-layer structure fruit drying process.