The invention discloses a floating sanding machine which comprises a frame, a polishing motor, a main driving wheel, a main floating sanding wheel, an auxiliary floating wheel, at least one abrasive belt driving wheel, an abrasive belt, a connecting mechanism, a front floating arm, a rear floating arm, a floating cylinder and a tension mechanism. The polishing motor is connected with the main driving wheel in a driving manner, the annular abrasive belt is sleeved on the peripheries of the main driving wheel, the main floating sanding wheel, the auxiliary floating wheel and the abrasive belt driving wheels, the main floating sanding wheel is connected with the auxiliary floating wheel through the connecting mechanism, one end of the front floating arm is rotatably connected onto a wheel shaft of the main floating sanding wheel, the other end of the front floating arm is rotatably connected onto a frame, one end of the rear floating arm is rotatably connected onto a wheel shaft of the auxiliary floating wheel, the other end of the rear floating arm is rotatably connected onto the frame, a cylinder body of the floating cylinder is fixed onto the frame, and a piston rod of the floating cylinder is connected with the front floating arm. A product is sanded and polished in a floating manner in different directions, the tension of the abrasive belt can remain unchanged, and sanding quality is ensured.