The utility model discloses a jig of a commercial vehicle battery replacement system. The jig of the commercial vehicle battery replacement system comprises a base, vertical beams, guide wheels, a left stop structure, a right stop structure, a rear stop structure and a locking mechanism, wherein the base is provided with a power battery box inlet on the front end; more than two vertical beams used for extending along the pulling direction of a power battery box are arrayed in the base at interval; the guide wheels used for matching with the power battery box in a guiding way are rotatably assembled on the vertical beams at interval along the pulling direction of the power battery box; the left stop structure and the right stop structure which are used for matching with the power battery box in a limiting way are respectively arranged at the left side and the right side of the power battery box; the rear stop structure used for matching with the power battery box positioned on a push-in base in a limiting and stopping way is arranged on the rear part of the base; and the locking mechanism used for preventing the power battery box from exiting is arranged on the inlet in the front end of the base. The jig of the commercial vehicle battery replacement system has the advantages of simple structure, safety and convenience for use, lower manufacture and use cost, and convenience for maintenance, is favorable for effectively solving the safe replacement problem of the traditional commercial vehicle battery pack replacement system in replacing a power battery pack and reducing the cost of the commercial vehicle battery replacement system.