The invention discloses a constant pressure cabin used for a cigarette smoking machine and a suction experiment method thereof, and aims at providing a use-facilitating constant pressure cabin used for a cigarette smoking machine and a suction experiment method thereof. The constant pressure cabin comprises a cabin body, and a smoke pipe is led out of the cabin body. The constant pressure cabin also comprises an enclosed exhaust auxiliary cabin. The exhaust auxiliary cabin is internally provided with a flow guide plate which separates the internal cavity into an exhaust cavity and a balance cavity which are communicated. The smoke pipe is communicated with the exhaust cavity of the exhaust auxiliary cabin. The exhaust cavity of the exhaust auxiliary cabin is provided with an exhaust pipe equipped with an exhaust valve. The balance cavity of the exhaust auxiliary cabin is communicated with the cabin body through a pressure balance pipe, and an air filter is arranged on the pressure balance pipe. The cigarette smoking machine and other equipment can be ensured to perform inspection work under the environment of the simulated standard atmospheric pressure so that the measurement accuracy of the detection equipment under the nonstandard atmospheric pressure can be enhanced.