a robot body, provided with a moving mechanism configured to controllably move the robot body forward or backward; wherein there is a weight difference between left and right sides of the robot body; wherein the moving mechanism comprises a driver, which is connected to a heavier side of the left and right sides of the robot body, and drives the moving mechanism;

wherein the robot body is provided with a fluid inlet-outlet and at least one first fluid inlet communicated with the fluid inlet-outlet through a first fluid channel, and at least one first fluid outlet communicated with the fluid inlet-outlet through a second fluid channel; the first fluid channel and the second fluid channel are communicated; wherein the at least one first fluid inlet and the at least one first fluid outlet are located at a bottom of the robot body; wherein the first fluid channel is provided with at least one filter chamber communicated with the at least one first fluid inlet; wherein the fluid inlet-outlet is provided with a fluid driver configured to controllably apply a suction force to the at least one first fluid inlet or a discharge force to the at least one first fluid outlet; and

a controller, provided in the robot body, connected to and controlling the operation of the moving mechanism and the fluid driver; wherein, when the robot body operates on a floor of a pool, a combination of the discharge force and the weight difference steers the pool-cleaning robot; when the robot body operates on a wall of the pool, a combination of the suction force and the weight difference steers the robot body.