An operation method of a deposition machine is provided. The method comprises providing a chamber, providing a first pipeline and a second pipeline, wherein a first end of the first pipeline and a first end of the second pipeline are connected to the chamber, and a part of the second pipeline passes through a sidewall of the first pipeline and extends into an interior of the first pipeline to define an extension part. A diameter of a second end of the extension part is W1, a diameter of a middle part of the extension part is W2, and a diameter of a part of the second pipeline outside the first pipeline is W3, wherein W2 is greater than W3 and W3 is greater than W1. A wafer is placed in the chamber, and a deposition step is performed.