A terminal guidance law with impact angle constrained is designed to intercept maneuvering targets in this paper. Firstly, the sliding mode guidance law is put forward on the premise of autopilot with ideal dynamic delay. The convergence property within finite time is demonstrated. Furthermore, the guidance law is extended using nonlinear backstepping method in the case of dynamics delay of autopilot. The simulation results demonstrate that the proposed guidance law provides better performance during the autopilot with actual delay and target makes escape maneuver.