The invention discloses a tool cabinet opening and closing mechanism which comprises a cabinet body and a cabinet cover. An extending portion is arranged on the side, close to the cabinet cover, of the cabinet body; a connection frame is arranged between the extending portion and the cabinet cover and comprises a rotary portion rotationally installed on the extending portion; first parallel bending portions are arranged at the two ends of the rotary portion and located on the outer side of the extending portion; the first bending portions are provided with second bending portions perpendicular to the first bending portions; and the second bending portions are rotationally installed on the cabinet cover. By the adoption of the tool cabinet opening and closing mechanism, on the premise that tools are picked up and stored with the proper opening degree between the cabinet body and the cabinet cover, the number of parts is effectively decreased, the cost is reduced, assembly is facilitated, and the assembly efficiency is improved; and meanwhile, the structure is simple, operation is convenient, and practicability and use convenience are greatly improved.