It is important to master the law of soil water infiltration for the rational development of irrigation scheme, setting irrigation parameters and improving irrigation technology. In order to explore the law of soil water infiltration under the condition of moistube-irrigation, HYDRUS-3D finite element model was used to simulate the soil water infiltration under micro-irrigation. The effects of initial pressure head and soil texture on soil water infiltration were discussed. The numerical simulation results showed that the wetting body was diffused around the micro-tube in the vertical section of soil water infiltration, and the diffusion rate was positively correlated with the initial pressure head. The average infiltration rate of soil water was 1.85cm/h in the first 5 hours, the average infiltration rate was 0.79cm/h between the 6th hour to 15th hour, and the average water infiltration rate in the period from 16th hour to 36th hour was 0.59cm/h. The maximum soil moisture content appeared around the micro fabricated tube and tended to decrease to the periphery. The migration distance of soil wetting peak increased with the increase of initial pressure head. The infiltration rate of micro-irrigation increased in three soil layers (sandy loam, loam, loam loam). When the pressure head was -180cm, the average water diffusion rates of the three soils were 0.69cm/h, 0.53cm/h and 0.46cm/h, respectively.