A method for collecting dust from a single crystal growth system includes providing dry air and oxygen into an exit pipe connecting to the single crystal growth system, blowing a first inert gas into the exit pipe to compel the dust oxide toward a dust collecting device, collecting the dust oxide by the dust collecting device; and providing a rotary pump to transport residues of the dust oxide backward. The oxygen reacts with the unstable dust for forming dust oxide. The exit pipe is used to exhaust unstable dust from the single crystal growth system.