Abstract: An exhaust system connected to a process chamber in a semiconductor processing device includes: a switching device; a first pressure control mechanism; and a second pressure control mechanism. The switching device is connected to the process chamber, and is connected to the first pressure control mechanism and the second pressure control mechanism for switching between the first pressure control mechanism and the second pressure control mechanism to discharge the gases and control the pressure in the process chamber. The first pressure control mechanism includes a first pressure control pipeline and a first controller, and the first pressure control pipeline is connected to the switching device and is used to discharge the gases in the process chamber. The first controller is disposed at the first pressure control pipeline to control the process chamber to maintain a first pressure when the first pressure control pipeline discharges the gases.