The sliding mode guidance law of the reentry phase of vehicle was studied considering terminal velocity and impact angle constraints.The sliding mode guidance law satisfying terminal angle was derived,the guidance equations were expressed in longitudinal and lateral plane respectively,and the needed guidance command of angle of attack and sideslip angle were generated.Guidance command of angle of attack and sideslip angle were obtained considering the terminal velocity and falling angle.The synthesized guidance command was the sum of needed guidance command and appended guidance command.Simulation results indicate that the attitude of vehicle is stable and the vehicle is guided to target precisely.The changes of impact point deviation,terminal velocity and impact angle with target velocity were analyzed.The result shows that:the sliding mode guidance law and the optimal guidance law have similar performance on impact angle control,but the former performs much better on terminal velocity and impact point deviation.Therefore,the sliding mode guidance law is robust to maneuvering target.