Based on the theory for water movement in non-saturated soil, a mathematical model of point source infiltration under adequate water supply was established and solved by using SWMS-3D software. The point source infiltration characteristics were simulated with several typical soils under adequate water supply. According to the simulation results, the infiltration characteristics and related affecting factors was analyzed. It was shown that the cumulative infiltration curve can be well described using Philip model. With same soil texture and bulk density, the sorptivity(A) increased with film hole diameters. The steady infiltration rate (S) increased with film hole diameter and slightly increased with irrigation depth. Furthermore, the simpli-fied infiltration model was proposed for point source infiltration under adequate water supply, including film hole diameter and irrigation depth as parameters. The simplified model was then tested by infiltration experi-ments using typical soils from Loess Plateau and experimental data reported in the studies of the other re-searchers. It was concluded that the simplified infiltration model accurately reflects the point source infiltra-tion characteristics under adequate water supply and can therefore be applied readily to determine the sorptiv-ity and steady infiltration rate.