The invention discloses a floor sweeping, dust collecting and humidifying integrated machine used in a building under construction. The machine comprises a rack, a dirt collecting box, a sweeping assembly, a dust collecting box and a humidifying assembly, wherein handrails are arranged on the rack; the rack comprises a sweeping cavity, a collecting cavity and a humidifying cavity which are sequentially arranged separately from front to back; the dirt collecting box is arranged in a lower chamber in a sliding mode; the sweeping assembly is mounted within the sweeping cavity; the dust collectingbox is arranged in the upper chamber in a sliding mode; the dust collecting assembly comprises an arc-shaped dust collecting cover arranged above the sweeping cavity, a dust collecting pipe communicating with the top end of the dust collecting cover, a motor fixedly arranged in the humidifying cavity, a rotating rod rotatably connected with an output shaft of the motor, a second worm wheel arranged on the rotating rod, a second worm rod meshed with the second worm wheel and a fan arranged on the rear side of an exhaust cavity; the humidifying assembly comprises a water storage box located inthe humidifying cavity and located behind the motor; and a humidifying hole is formed in the rear side of the humidifying cavity. The machine has the beneficial effects that dust collecting and humidifying can be assisted in a floor sweeping process.