To investigate the mechanism of tire-pavement partial hydroplaning, finite element numerical method was applied to establish 175-70-R15 tire model and water-air composite model. Coupled Eulerian-Lagrangian method was applied to establish the three-dimensional numerical model of patterned inflation tire hydroplaning. The simulation investigated the influence of water film thickness and tire velocity on the mechanical responses of tire and discussed the impact of tire motion state on the partial hydroplaning process. The results show that, with the thicker water film, the water lifting force increases, while the longitudinal force provided by pavement decreases, which means that the tire enters into the complete hydroplaning earlier. With the increase of tire velocity, the longitudinal water drag force increases, which occurs more obviously when the water film becomes thicker. The relationship between water lifting force and water film thickness and tire velocity is regressed into an equation. It is determined that tire with ABS enters complete hydroplaning earlier than that in free rolling statement.