The invention discloses a total hip replacement surgery auxiliary instrument which comprises a grooved bed board for replacement and fixed rods. Longitudinal slide grooves are evenly formed in the grooved bed board and are each of a big-end-down structure. The fixed rods move through the slide grooves. A base which can not be moved out of the corresponding slide groove is arranged at the bottom of each fixed rod. A fastening structure for fixing the fixed rod to the grooved bed board is arranged on each fixed rod. In addition, an insertion hole is formed in each longitudinal slide groove of the grooved bed board, or a transverse groove is formed in the grooved bed board so that the fixed rods can be inserted in the slide grooves. According to the total hip replacement surgery auxiliary instrument, the fixed rods can be continuously arranged, the positioning precision is ensured, operation is easy, and use is convenient.