In order to improve the adaptability of the 6 legged robot to the staircase obstacles, a semicircular leg type 6 legged robot is designed. According to the structure characteristics of the robot, the 4 legged gait of the 6 legged robot climbing staircase is planned. Based on gait planning, the kinematic model of quadruped gait is analyzed and established. By adjusting the rotation angle and swing angle of each leg, the dynamic simulation of the robot is carried out with ADAMS software. The simulation results show that the structure design of the 6 legged robot is reasonable, the quadruped gait with climbing stairs can achieve continuous climbing stairs, and the centroid displacement curve of the robot continually keep smoothly as time goes by, which validates the validity of the kinematics model.