Abstract: The objective of this study was to explore the effect of different initial soil water contents on the characteristics of the wetting body and to establish the quantitative model of ?lm hole irrigation between cumulative in?ltration and the shape of the wetting body. Laboratory experiments and HYDRUS numerical simulation were carried out. The reliability of the simulation results using HYDRUS software in film hole irrigation was verified by laboratory experiment, and the results showed that the R2 of HYDRUS simulation and laboratory experiment results (wetting front migration distance and cumulative infiltration amount) were both close to 1, and the absolute value of percentage of bias was less than 10%, indicating a good fitness. Based on this, the dynamic characteristics of Xi'an silt loam in film hole irrigation under different initial soil water content were simulated. The experimental results showed that the shape of the wetting body formed by film hole irrigation was approximately half of a rotating ellipsoid, and the shape of wetting front curve could be expressed using an elliptic curve equation. The horizontal and vertical migration distances of the wetting front were semi-major and semi-minor axis of the ellipse, respectively. When the initial soil water content was as low as around 0.1 cm3/cm3, the soil water content on the wetting body radius from the center of the film hole to the surface of the wetting front decreased gradually and the change rate of soil water content increased gradually, reaching the maximum near the wetting front. Moreover, the distribution of soil water content on the wetting body radius could be accurately expressed by using an elliptic curve equation. As the initial soil water content of the wetting body increased gradually, the water content gradient in the wetting body decreased, the water distribution became more uniform and the water content distribution curve of the wetting body radius gradually changed from an elliptic curve to a gentle curve close to a straight line. According to the distribution law of soil water content in the wetting body, the model of cumulative infiltration considering initial soil water content was established. The model showed that the cumulative in?ltration of ?lm hole irrigation was proportional to the third power of the equivalent radius of the wetting body, and the wetting body radius was equal to the geometric mean of the horizontal and vertical migration distances of the wetting body. In order to verify the accuracy and applicable scope of this model, the HYDRUS simulation results of three typical soils (silt, silt loam and loam) and five different film hole radius (1, 2 , 3, 4 and 5 cm) were used to verify the model. For the silt, silt loam and the loam soils, when the initial water content was not higher than 0.25 cm3/cm3, the R2 of calculated cumulative infiltration and simulated value using HYDRUS were both close to 1, and the absolute value of percentage of bias was less than 10%, which showed that the model had good applicability in silt, silt loam and the loam when the initial water content was not higher than 0.25 cm3/cm3. In addition, for the different film hole radii, the R2 of calculated cumulative infiltration and simulated value using HYDRUS model were close to 1, and the absolute value of percentage of bias was less than 10%, which suggested that the model had good applicability to the conditions of different film hole radii. Since this model reflected the relationship between the cumulative infiltration and the shape of the wetting body, for crops, this model was superior to the traditional empirical models such as the Kostiacov model in calculating the irrigation demand of crops to a certain extent. This study revealed the characteristics of the wetting body of film hole irrigation under different initial water contents and established a model for calculating cumulative infiltration, which provided valuable information for the precise irrigation of film hole irrigation.