The invention discloses a back slurry pipe connecting auxiliary device of a slurry shield trolley and a use method thereof. The back slurry pipe connecting auxiliary device of the slurry shield trolley comprises a rotary portion and a fixed portion. The rotary portion comprises a monorail rotary beam, a rotary beam lifting device and a rotary beam sling. The rotary beam lifting device comprises atraveling unit and a lifting unit, the lifting unit is connected with one end of the rotary beam sling, and the other end of the rotary beam sling is bound to the end of the front side of a slurry pipe. The fixed portion comprises a monorail fixed beam, a fixed beam lifting device and a fixed beam sling. The fixed beam lifting device comprises a traveling unit and a lifting unit, the lifting unitis connected with one end of the fixed beam sling, and the other end of the fixed beam sling is bound to the end of the rear side of the slurry pipe. The connecting auxiliary device is designed at thepipe connecting side of a frame body of the slurry shield trolley, mechanical construction of pipe connecting operation is realized, the problem of low efficiency during manual connection of slurringpipelines in the past is solved, the work period is saved, and the construction cost is lowered.