In the lunar-planetary exploration, most of landers made a landing on flat areas of surface, because there are a lot of rocks craters and hills on lunar-planetary surface. For the next generation lunar-planetary exploration, the development of a highly accurate landing technology is demanded to land on the complex terrain. The navigation-guidance technology and hazard avoidance have been studied for the safe landing. Moreover the development of landing leg is required for the safe landing in the final phase of landing sequence. This paper presents the development of experimental system of active landing leg, and examine the landing shock response. In addition, we consider the effectiveness of active landing leg and the application to the control method of lander's overturn prevention.