Safety lifeline protection device for building construction

The utility model relates to the technical field of safe lifeline, in particular to a safe lifeline protection device for building construction, which comprises two support columns, a common cable and a standby cable are fixedly arranged between the two support columns, the common cable is positioned above the standby cable, and the standby cable is positioned above the common cable. A sliding clamping mechanism is arranged between the common cable and the standby cable, the sliding clamping mechanism comprises a box body, a first through hole and a second through hole are formed in the upper end and the lower end of the box body in a penetrating mode respectively, and lower rolling wheels are rotationally arranged at the positions, close to the first through hole and the second through hole, in the box body; and an upper roller is rotationally arranged at the position, close to the upper portion of each lower roller, in the box body, the common cable penetrates through the first through hole, and the standby