Abstract: A control strategy was proposed to ameliorate the trotting movement of quadruped robots on a slope. A compound cycloid line was adopted in this strategy to track the trajectory of the robot so that the instant impact on the feet of quadruped robot at phase change points could be reduced. Certain values of posture adjustment could be acquired according to stability analysis by using the distance between the projective point of the center of mass(COM) on the slope and supporting line as the stability margin. The simulation results from the virtual prototype model in ADAMS show that the posture control strategy proposed in this paper is reasonable, feasible and effective in terms of improving the motion stability of the quadruped robots on a slope.