A dust-free multifunctional cut machine, including a worktable board, a machine case carrying the worktable board, a rod assembly arranged on the top of the worktable board, a frame and a cutting assembly comprising a cutting blade and a motor for driving the cutting blade for rotation, and a dust suction assembly arranged between the output shaft end of the motor and a cutting blade and having a spiral casing and a dust suction vane, wherein, the spiral casing includes a dust suction inlet and a dust exhaust outlet, the rod assembly includes a rod fixture and a slide bracket, the frame is connected with the slide bracket through the frame rotating seat and the frame moves back and forth through the rod with the use of the slide bracket. The dust-free multifunctional saw has three functions including bench sawing, miter sawing and automatic dust collection.