The invention provides a novel overhead line residual current detection device comprising a flexible Rogowski coil, a Rogowski integrator and a support pole member; the support pole member comprises a U-type rod and a pole; the U-type rod is fixedly connected with the top of the pole; the flexible Rogowski coil is arranged along the U-type rod, and the head end and tail end of the flexible Rogowski coil are not connected; the output end of the flexible Rogowski coil is connected with the input end of the Rogowski integrator; in usage, the support pole member is lifted so as to sleeve the flexible Rogowski coil on a tested current carrying line; the flexible Rogowski coil is matched with the Rogowski integrator so as to detect the residual current on the current carrying line. The flexible Rogowski coil, the Rogowski integrator and the support pole member are combined so as to fast, reliably and safely detect the line residual current.