In order to achieve simultaneous saturation attack on a same target of multi-missile cooperatively, and designs remaining impact time estimation method based on the velocity prediction information under time-varying velocity and the missile impact-time-control method are designed. Classical PNG law is adpoted in the longitudinal plane, at the same time, the missile adjusts the remaining time through maneuvering in lateral plane. In addition, three-dimensional model of coupled longitudinal and vertical planes is adopted in this paper. Simulation results verify that the method proposed in this paper can accurately estimate the remaining impact time based on priori knowledge of future velocity profile, and then effectively control the impact time.