An autonomous moving floor-treating robot and a control method thereof for edge-following floor-treating are provided. The control method includes the following steps: the floor-treating robot collides with an obstacle and is deflected toward the direction away from the obstacle by a basic angle after the collision, measures an initial signal strength value by a side-looking sensor after the deflection, and then moves on and treats the floor; a real-time signal strength value is acquired by said side-looking sensor alter the robot runs for a predetermined time; the difference value between said two signal strength values is compared, and whether the difference value is in a predetermined range is judged, if yes, the robot keeps moving and treating the floor, if not, the robot is driven to be deflected by an adjusting angle and acquires the current real-time signal strength value; the difference value between said current and the last real-time signal strength values is compared, and whether the difference value is in a predetermined range is judged, if yes, the robot keeps moving and treating the floor, if not, the steps of deflection, comparing and so on are implemented. The present invention is unaffected by the media of the obstacle, and can effectively treat the edge region of the obstacle.