The invention discloses a cutting device for machining and a using method. The cutting device comprises a workbench, a transverse plate is fixedly connected to the center of the top of the workbench, fixing frames are fixedly connected to the centers of the two sides of the top of the transverse plate, and mounting plates are fixedly connected to the front side and the rear side of the bottom of one side of each fixing frame; and the bottoms between the opposite sides of the mounting plates are movably connected with communicating pipes through rotating shafts. Through cooperative use of a three-way pipe, a dust inlet pipe, an exhaust fan, a dust outlet pipe, a dust storage box, a cutting wheel, a first threaded rod, a movable sleeve, a threaded pipe, a second threaded rod, a gear motor, the fixing frames, an electric telescopic rod, a clamping plate, a hose, the communicating pipes, a dust suction hood and a driving motor, the problems that the angle of an existing pipe cutting device is not convenient to adjust, in the cutting process, the accurate cutting effect cannot be achieved, meanwhile, a large number of waste chips can be generated in the cutting process and are very troublesome in cleaning, and the working strength of people is increased are solved.