Abstract: Computational simulation of the water-entry cavity following the water-entry is carried out. During the computation, the Navier-Stokes equations are solved with the discretization of Finite-Volume Method, and VOF (Volume of Fluid) and dynamic mesh method are used for the multiphase flow and the movement of the water-entry body, respectively. The computation results of the air-cavity shape of water-entry of sphere are directly compared with the ‘ideal cavity' proposed by A. May, showing that the computation methodology properly captures the key features in the early stage of constant speed vertical water-entry cavity, and in particular gives a reasonable prediction of the outline of air-cavity in the early stage of water-entry, and of the history of the maximum radius of the air-cavity. At the same time the water-entry cavity history and air-cavity wall kinematics of the inverted truncated cone of 150 degree in the early stage life of the water-entry are investigated by computation, and the results show that the history of air-cavity wall movement following the water-entry body with different outline features are similar. And at the end of this paper the time of the surface closure of the air-cavity of the inverted truncated cone of 150 degree are also investigated.