Supporting device for sliding door of vehicle

The invention belongs to the technical field of vehicle sliding doors, and provides a vehicle sliding door supporting device which comprises a vehicle door piece, a rotating frame, a supporting arm assembly, a double-roller assembly and a lower guide rail, one part of the lower guide rail is bent towards the outside of a vehicle, and a vehicle sliding door is installed on the vehicle door piece. The vehicle door piece is hinged to the rotating frame and then connected with the supporting arm assembly, the supporting arm assembly is connected with the double-roller assembly and used for sliding supporting, the double-roller assembly is provided with a guide roller, and the guide roller can slide in the lower guide rail. The lower guide rail has the advantages that the lower guide rail is divided into the overlapping part and the forking part, the lower guide rail is bent towards the outside of the vehicle, the load bearing of the whole vehicle sliding door is changed into the load bearing of the upper end, and