The invention discloses a belt sanding tool installed at the tail end of a robot, and relates to a polishing tool. With the belt sanding tool installed at the tail end of the robot, the problem that an existing polishing tool for a robot is high in force control difficulty, requirement on control system performance, and cost is solved. A belt tensioner is installed on the upper end face of a framethrough a belt tensioner support. A low-friction air cylinder is fixedly installed on the frame and located below the belt tensioner support. A servo electric cylinder is horizontally installed at the bottom of the frame. A motor supporting plate is fixedly installed on the front end face of the frame. An output shaft of a servo motor is in transmission connection with a driving wheel through a synchronous belt. A contact wheel is connected to the servo electric cylinder through a contact wheel support. A high-precision sensor is installed on the contact wheel. The high-precision sensor is electrically connected with the servo electric cylinder. A transition wheel is installed in the middle of the frame. An abrasive belt is installed on the driving wheel, the belt tensioner and the contact wheel in sequence. The transition wheel is arranged on the part, between the belt tensioner and the contact wheel, of the abrasive belt in a pressing manner. The belt sanding tool installed at the tail end of the robot is used for aerospace product manufacturing and automobile making grinding.