The invention discloses a straight rod porcelain insulator replacement auxiliary device, which comprises a positioning clamp, a lifting mechanism and a tensioning mechanism, wherein the positioning clamp comprises a [-type clamping seat; the lifting mechanism comprises an upper fixing plate, a lower fixing plate, a [-type sliding block and a screw rod, the lower fixing plate is arranged on the [-type clamping seat, the upper fixing plate is connected with the lower fixing plate via two guiding rods, the upper part of the screw rod is sleeved in a through hole arranged in the upper fixing plate, the lower end of the screw rod is sleeved in a countersink in the lower fixing plate, the [-type sliding block correspondingly sleeves the guiding rods and the screw rod, and the front end of the [-type sliding block is provided with two supporting casings; and the tensioning mechanism comprises a pull pipe and an L-type pull rod, the L-type pull rod sleeves two ends of the pull pipe in a threaded connection mode, the bottom end of the L-type pull rod is provided with a clamping mechanism, and the pull pipe is sleeved in the two supporting casings. By using the tensioning mechanism and the lifting mechanism, pullback and lifting of a power line at the top end of the porcelain insulator can be realized smoothly, and replacement of the porcelain insulator is facilitated.