The utility model discloses an open type stay wire warning rod, including first semicircle pipe and second semicircle pipe, first semicircle pipe forms the pipe with the same and mutual concatenation of second semicircle tubular construction, installs the main part by many round tube composition first semicircle pipe and second semicircle pipe middle position are provided with the recess, the recess endotheca is equipped with the retainer plate, and both sides are equidistant about the recess is provided with a plurality of warning areas, both ends installation department is the interface about first semicircle pipe and the second semicircle pipe, be equipped with C type opening in one side inboard of interface, the another side inboard of interface is equipped with the flange, this device structure is ingenious, through the concatenation of both ends about two semicircle pipes with the opening form, and be equipped with recess and fixed with retainer plate sealing contact at two semicircle pipe middle positions, the stability of fixed back body has been guaranteed, and convenient the dismantlement, through sleeve and the cylinder that sets up a plurality of matched stacks cover on half inner wall of circular pipe, further strengthen the fastness after the pipe installation.