The polished rod clamp is of hinge-jointed butterfly structure, it is fixed on the polished rod as retaining device for the rope hanger. It makes the pumping unit horsehead connected with polished rod through rope hanging device, and then the polished rod append and supprt the load of sucker rod string. The polished rod clamp is an important part connecting oil pump and sucker rod, it is required not only reliable, have a certain capacity, but also can not cause damage for sucker rod.