The utility model discloses anti -theft bolt formula side checkpost belongs to the improvement of oil recovery machinery, concretely relates to polished rod checkpost for the beam -pumping unit, the the device side of including checkpost, fixing bolt and theftproof pin, square checkpost include first checkpost and second checkpost by hinge pin joint, first checkpost and second checkpost opposite face be vertical to set up the cross -section for semicircle draw -in groove, first checkpost sets up rectangular channel and pin socket, the second checkpost corresponds the rectangular channel position and sets up connect the via hole, still including installing the screw thread pad in the draw -in groove, fixing bolt can pass the rectangular channel of first checkpost and the connect the via hole of second checkpost, theftproof pin including body of rod cross -section be triangle -shaped's precession end and is connected with the precession end, body of rod cross -section is for the circular shape locating pin, the locating pin other end is provided with the screw thread along the circumference, still include with the peaceful pad of the supporting nut of fixing bolt, the utility model discloses anti -theft bolt formula side checkpost, not only the centre gripping ability is better, and convenient operation has the theftproof protective capability moreover.