Carriage cover frame structure

The invention discloses a carriage cover frame structure, and belongs to the field of pickup truck rear box covers. A carriage cover frame structure covers a rail of a truck carriage or directly covers the truck carriage, and comprises two side fences which are arranged in parallel and extend in the length direction of the carriage; the front fence is connected with the ends, close to the truck cab, of the two side fences; the rear fence is connected with the ends, close to the tail of the truck carriage, of the two side fences; the carriage cover frame structure further comprises a supporting piece located between the front fence and the rear fence so as to support a shielding piece installed on the carriage cover frame structure. The middle connecting piece is used for connecting the supporting piece and the sidebar; the middle connecting piece comprises a base part installed on the sidebar; the insertion part is connected to the base part and is inserted into the supporting piece so as to realize the conne