Combustible gas subsystem of fuel cell and control method of combustible gas subsystem

The invention discloses a combustible gas subsystem of a fuel cell and a control method of the combustible gas subsystem. The combustible gas subsystem of the fuel cell comprises a gas inlet pipeline, a gas exhaust pipeline, a first circulation pipeline and a second circulation pipeline. The air inlet pipeline is connected with an air inlet of the electric pile; the gas inlet pipeline is used for connecting gas into the electric pile; an ejector is arranged in the air inlet pipeline; the exhaust pipeline is connected with an exhaust port of the electric pile; the exhaust pipeline is used for exhausting waste gas in the electric pile; the first circulating pipeline is connected between the gas inlet pipeline and the gas exhaust pipeline; the first circulating pipeline comprises a first circulating branch and a second circulating branch which are connected in parallel; the first circulating branch is connected between the outlet of the ejector and the exhaust pipeline, and a circulating pump and a first air inl