Connecting flange of automobile exhaust system

The utility model relates to a connecting flange of an automobile exhaust system. The connecting flange is characterized by comprising a disc-shaped connecting flange body, wherein a through hole is formed in the center of the connecting flange body, a plurality of bolt holes which are uniformly distributed are formed in the periphery of the through hole, and a semicircular blind groove is arranged on the edge of a non-machined surface of the connecting flange body. The connecting flange is simple in structure; the blind groove is formed in the non-machined surface, so that an assembling surface and a non-assembling surface can be distinguished conveniently by the assembling worker, the working efficiency can be improved, and the quality potential hazard can be avoided; meanwhile, the blind groove can be used as a positioning and orientation benchmark when the assembling surface and the bolt holes are machined, and convenience in machining can be realized.