The invention belongs to the technical field of automobile parts, and particularly relates to a circular plug cover fixing structure. The circular plug cover fixing structure comprises a plug cover. An axial locating ring is arranged at the bottom of the plug cover. Fixing clamp buckles and guide locating columns are arranged in the end portions of the locating ring. According to the circular plug cover fixing structure, the plug cover is fixed in a button installation hole through the design of the simple clamp buckles and the simple locating columns, the structure is simple and convenient in installation, the plug cover is prevented from moving in the installation hole, and the structure can be widely used in a passenger car one-key starting system.