Abstract: In the process of calculating infiltration, HYDRUS- 1D model has some problems such as difficult to determine the model parameters, longer calculation time and non- convergence. The HYDRUS- 1D model is used to calculate the infiltration curve. On this basis, the input and output data are reconstructed according to the construction principle of the proxy (or surrogate) model, and the proxy model expressing the functional relationship between input and output is established, so as to improve the efficiency and applicability of the model. The proxy model is verified under the conditions of stable rainfall and variable rainfall intensity. The results show that under the condition of stable rainfall, the infiltration rate hydrograph calculated by the proxy model is consistent with the hydrograph calculated by HYDRUS-1D. Under the condition of actual variable rainfall intensity, when the rainfall intensity is greater than the soil infiltration capacity, the proxy model and HYDRUS-1D model coincide. When the precipitation suddenly decreases in the process of same precipitation and the precipitation intensity is less than the actual soil infiltration capacity, The proxy model cannot consider the soil draining condition, and there will be a loss of accuracy in calculating the soil infiltration rate. The proxy model is further improved. After considering the influence of soil flow on soil moisture, the proxy model can simulate the abrupt change of soil infiltration rate when the rainfall intensity is greater again than the actual infiltration capacity of soil.