Abstract: A floating photovoltaic cable manufacturing device for offshore photovoltaic systems and a manufacturing method thereof are provided. The device includes a cable body that passes through a rack at a constant speed, a winding frame is provided on one side of the rack, the winding frame is connected to a driving motor through a transmission mechanism, a rotation of the winding frame drives armored steel sheets to be wound on a surface of the cable body; a spot-welding gun provided in the rack through a regulation mechanism, a bottom of the spot-welding gun is aligned with the armored steel sheets; and a resistance band sleeved on surfaces of two sets of driving shafts, the resistance band is attached to the armored steel sheets, and a movement of the cable body enables the driving shafts to rotate on two sides of a connection rack.