The invention relates to a suspension pay-off device for a power transmission tower line. The power transmission tower comprises a base, a power transmission tower body and a cross arm, the power transmission tower body is connected with the base through a fixing piece, the pay-off device which is vertically connected with the cross arm comprises a suspension pulley and a suspension assembly, thesuspension assembly is composed of a vertical piece and a balance adjusting piece, wherein the vertical piece is vertically arranged, and the two ends of the balance adjusting piece are correspondingly connected with the two ends of the suspension pulley and connected with the vertical piece. According to the paying-off device, a "double-hanging-point" suspension mode of an existing double pulleyis changed, a "single-hanging-point" suspension mode of a double-pulley is adopted, the "single-hanging-point" suspension mode is suspended on the iron tower cross arm through the vertical piece, whena splicing tube protection device enters the double-pulley initially, a suspension angle can be automatically adjusted by the "single-hanging-point" suspension mode of the double-pulley, the self-adaptive splicing tube protection device passes through a pulley envelope angle, wire stress at a fracture of the splicing tube protection device is reduced, and a wire is protected.