Abstract: In order to realize the stable motion of the quadruped robot under the conditions of complex terrain environment, limited energy supply and unpredictable interference, and to improve the ability of the quadruped robot to traverse complex terrain, the particle swarm optimization algorithm was used to optimize the classical walking gait parameters. An exploratory gait was proposed, being of easy implement and adapt to different terrains. Needing not any terrain information sensed by stereo vision or LIDAR, the proposed exploratory gait was arranged with the IMU sensor and the foot force sensor to make the robot sense terrain directly. Several simulations and experiments were carried out for the proposed optimization method and gait strategy, verifying the performance of the proposed exploratory gait on uneven terrain.