Coating device for bottom surface of bridge and construction method thereof

The invention discloses a coating device for the bottom surface of a bridge. The coating device comprises a sliding rail groove I erected on the side wall of the bridge, jack supports are installed atthe two ends of the sliding rail groove I, and the sliding rail groove is provided with a sliding block driven by a motor to move back and forth on the sliding rail groove I. The coating device for the bottom surface of the bridge is characterized in that an upper pipe sleeve is connected to the lower part of the sliding block, the upper pipe sleeve is connected with a lower pipe sleeve in a hinged mode, and a motor II driving the lower pipe sleeve to rotate is installed on the side edge of the upper pipe sleeve; a steel wire rope retracting and releasing machine is installed on the sliding block; a steel wire rope penetrates through the upper pipe sleeve and the lower pipe sleeve, the steel wire rope retracting and releasing machine is connected to one end of the steel wire rope, and a clamping groove seat is co