The invention relates to a follow-up pulley and a method for hanging the follow-up pulley on an overhead line. The follow-up pulley includes a hook, a fixed pulley arranged at a lower end of the hookand a closing lock piece arranged at an upper part of the hook and slidably connected with an outer side of the hook; The hook comprises a lower hook body with an L-shaped structure and an upper hookbody with an inverted L-shaped structure, which are fixedly connected; The upper hook body and the lower hook body are mutually matched to form an opening and a groove for receiving a lead wire; A side of the lower hook body facing the opening is arranged in an arc shape; A locking piece integrally has an inverted concave structure, is slidably connected with that outer side wall of the top of thehook, and can move up and down to open or close the opening of the hook; The top of the closure lock piece is fixedly connected with a hanging ring.