The invention discloses a locking device for a vehicle inspection tool, which comprises a base plate, positioning vertical plates, a supporting and pushing rotatable cylinder, force receiving plates,and translating plates. The positioning vertical plate is fixedly connected to each end of the surface of the base plate, and the surface of the positioning vertical plate is fixedly connected with aninsulation plate. Layer dividing plates are fixedly connected on the surface of the insulation plate. The layer dividing plate is provided with a limiting hole. An elastic positioning column is provided in the limiting hole. The upper end of the positioning vertical plate is fixedly connected to the bottom surface of a top plate. A servo motor is fixedly connected on the surface of the top plate,and a rotating shaft thereof passes through the surface of the top plate and is fixedly connected to the top surface of the supporting and pushing rotatable cylinder. The locking device for a vehicleannular component inspection tool simultaneously detects a plurality of annular components, and displays the wear degree of each annular component according to scale marks on the surface of a measuring plate, thereby recording data conveniently and improving the detecting efficiency of the annular components.