Frame structure of folding cart

The utility model discloses a frame structure of a folding cart, which is characterized in that an X-shaped connecting frame is arranged between a bottom frame and a top frame, a supporting frame for supporting the top frame is arranged on the bottom frame, the top end of the supporting frame is detachably connected with the top frame, the bottom end of the supporting frame is hinged on the bottom frame, a second sliding block which is connected with the supporting frame in a sliding mode is arranged on the supporting frame, and the bottom end of the supporting frame is hinged on the bottom frame. A connecting rod is hinged to the second sliding block, the other end of the connecting rod is hinged to the sliding base, the supporting frame drives the sliding base to move on the bottom frame through the connecting rod, and the sliding base drives the first sliding block to move on the top frame through the connecting frame. The folding device has the advantages that the supporting frame drives the sliding seat