The utility model discloses a flange, which comprises an annular plate and a pipe. The annular plate is sleeved on the pipe and provided with a positioning hole and a plate wall used for clamping the pipe. The technical problem of connection between a pipe flange and unweldable materials in the prior art is solved by means of the plate wall of the flange. Moreover, the flange is simple in construction, simple and stable in structure, high in connection strength, quite convenient in mounting and demounting and reusable, and waste is reduced.