The space-borne laser altimeter can be widely used in a variety of scientific research of topography, such as ice sheet and vegetation cover change. For quantitative application of the space-borne laser altimeter data, the ground-based laser altimeter calibration method was investigated and a laser altimeter ground-based simulation system was designed. The system consists of detector arrays and high precision timing system for the verification of laser altimeter pointing angle and timing. The performance of the system is tested in the laboraroty and simulated by software. Resuts show that the detector can detect the spot of average energy 3 nJ/cm2, and detection range is 1～16 nJ/cm2 with timing accuracy of 1.25 ns.