Abstract: During irrigation process, the soil structure of infiltration interface is changed with infiltration head increasing in water storage pit, which results in changing of soil water infiltration characteristics. In order to simulate the infiltration process of different infiltration heads, the improved Green-Ampt model of different infiltration heads was established based on mechanism of soil infiltration in different infiltration heads.?Effect of infiltration head on infiltration was reflected by the generalized saturated hydraulic conductivity. A series of experiments were conducted to verify the improved Green-Ampt model of different infiltration heads. The computational infiltration rate derived from the improved Green-Ampt model was in accordance with the experimental results under different infiltration heads. They indicate that the improved Green-Ampt model can effectively simulates infiltration process of different infiltration heads