Drainage device, dental workstation and drainage method thereof

The embodiment of the invention provides a drainage device. The drainage device comprises an air compressor; the air storage tank is connected with the air compressor; the drainage pipe is connected with the gas storage tank; wherein a first hole and a second hole are formed in the drainage pipe, the hole diameter of the first hole is smaller than the pipe diameter of the drainage pipe, the second hole is located between an outlet of the drainage pipe and the first hole or formed in the outlet of the drainage pipe, and during drainage, high-pressure water in the gas storage tank flows out through the first hole, the second hole and the drainage pipe. The first hole is formed in the drainage pipe connected with the gas storage tank, the hole diameter of the first hole is smaller than the pipe diameter of the drainage pipe, the first hole and the outlet of the drainage pipe are spaced by a certain distance, and the first hole and the pipeline between the first hole and the outlet of the drainage pipe play a rol