The invention discloses a back bolt screwing fixing device. The back bolt screwing fixing device comprises a first limiting plate and a second limiting plate which are arranged left and right, whereinbaffles are arranged on two sides of the first limiting plate and the second limiting plate; a handle is fixedly connected with the side wall of the second limiting plate; a strip-shaped cavity is formed in the middle of the second limiting plate; sliding grooves are formed in the lower ends of two sides of the second limiting plate; a double-end threaded rod is rotationally connected between opposite inner walls of the strip-shaped cavity; abutting plates are in threaded connection with two sides of the double-end threaded rod; the side walls of the abutting plates are glidingly connected with the inner wall of the strip-shaped cavity; two abutting rods are fixed on opposite side walls of the two abutting plates; tail ends of the two abutting rods penetrate through the inner wall of thestrip-shaped cavity and extend into the sliding grooves; abutting blocks are fixed at ends, positioned in the sliding grooves, of the abutting rods; tail ends of the abutting blocks are fixedly connected with the inner walls of the baffles. The back bolt screwing fixing device is reasonable in structure, can be adjusted according to the size of a back bolt piece, can finish fixing with one hand and is good in fixing effect and high in safety.