The invention discloses a crank connecting rod mechanism with a balanced structure and a fan. The crank connecting rod mechanism with the balanced structure comprises a crank and a connecting rod, and further comprises a balance part, wherein the partial structure of the crankshaft is always shielded by a balance assembly when the crank moves in a circumferential direction; and in an axis direction of the crank, the balance assembly is spaced from a synchronous motor by predetermined width, so that the crank is prevented from moving in the axis direction. According to the crank connecting rod mechanism, the balance assembly is arranged and can limit the movement of the crank in the axis direction of the crank; the connecting rod and the crank are in fastened connection, so that the axial jumping problem of the crank can be effectively avoided, friction caused by jumping is reduced, and noises caused by long-term use are avoided. Besides, the balance assembly for limiting the crank is arranged, so that dimensional tolerance requirements of parts are reduced, and therefore, the producing and manufacturing cost is further reduced, and the service lives of the parts are prolonged.