The invention discloses a steel pipe cut-off device for building construction. The steel pipe cut-off device for building construction comprises a rack and two fixing devices. The left inner side andthe right inner side of the rack are symmetrically and rotationally provided with two first threaded rods. The first threaded rods are connected with first threaded sleeves through threads. The outersides of the two fixing devices are fixedly connected with the two first threaded sleeves through connection frames correspondingly. Each fixing device is composed of a first sleeve, a second sleeve and a rotary table. According to the steel pipe cut-off device for building construction, circular ring gaps are formed between the first sleeves and the corresponding second sleeves, and placement ofend openings of steel pipes is facilitated; and meanwhile, a third motor drives a disk to rotate, when rotating anticlockwise, the rotary tables drive limiting blocks to slide towards the outer sidesthrough pushing rods, and therefore the steel pipes are fixed, the steel pipes are prevented from moving when being cut, the labor intensity of workers is reduced, and potential safety hazards are reduced.