The invention discloses a floor grinder for quick replacement of grinding heads, the structure of which comprises a grinding head device, a gear box, a motor, a water tank, a controller, a handle, a connecting plate, a hinged seat, cables, a support frame, a wheel frame, The movable wheel, the axle, and the supporting frame are equipped with a water tank, and the motor is installed in front of the water tank, and the motor is installed above the gear box through bolts. The two sides of the support frame are welded with a wheel frame, the wheel frame is set on one side of the gearbox, the wheel frame is provided with a through hole, the through hole matches the wheel shaft, and the two ends of the wheel shaft run through the wheel frame on both sides of the support frame And it is connected with the moving wheel, and the top of the supporting frame is welded with a hinged seat against the top. The invention is a floor grinder for quickly changing the grinding head, which can be quickly fixed by the block, and the guide post can prevent the blade from rotating, and the fixed Good effect, convenient and quick, improve work efficiency.