The invention discloses a pipeline butt joint connecting device for a construction site. The pipeline butt joint connecting device comprises a first fixing frame, sliding grooves are formed in the twosides of one end of the first fixing frame, and a flush mechanism is arranged in the middles of the inner walls of the two sliding grooves; the flush mechanism comprises main moving T-shaped rods, amain moving circular ring, a main fixing circular ring, a main double-head screw rod, a sawtooth rotating wheel, an inner sawtooth belt, a slave double-head screw rod, a slave moving T-shaped rod, a second fixing frame, a slave moving circular ring and a slave fixing circular ring; and the main moving T-shaped rods are arranged in the middles of the inner walls of the two sliding grooves. According to the pipeline butt joint connecting device, through arrangement of the main moving T-shaped rods, the main moving circular ring, the main fixing circular ring, the main double-head screw rod, thesawtooth rotating wheel, the inner sawtooth belt, the slave double-head screw rod, the slave moving T-shaped rod, the second fixing frame, the slave moving circular ring and the slave fixing circularring, the internal center points of two connecting pipes can be kept perpendicular, then extrusion installation between the two connecting pipes and a three-way connecting joint is facilitated, and the installation difficulty between the connecting pipes and the three-way connecting joint is reduced.