Boiler flue gas component measuring equipment, method, device and system

The invention relates to a boiler operation control technology, and particularly discloses boiler flue gas component measuring equipment, method, device and system, the equipment comprises a four-way switching device, and a first gas inlet port, a second gas inlet port, an exhaust port and a gas measuring port arranged on the four-way switching device; the first gas inlet port is in gas communication with the first measuring point; the second gas inlet port is in gas communication with the second measuring point; the gas measuring port is in gas communication with the flue gas measuring device; the four-way switching device is used for switching between a first communication state and a second communication state; wherein in the first communication state, the first gas inlet port is communicated with the gas measuring port, and the second gas inlet port is communicated with the exhaust port; and in the second communication state, the second air inlet port is communicated with the air measuring port, and the f