The invention discloses a gas component monitoring system and method. The system comprises a light source, a light filtering device, a gas storage tank, an interferometer, a light intensity sensor, a data acquisition device and a data processing device, wherein the light source is used for emitting light with stability; the light filtering device is used for filtering the light emitted by the light source to obtain light with a target wavelength and light intensity; the gas storage tank is used for storing gas to be detected and has a function of separating the gas to be detected; the interferometer is used for enabling the light emitted by the light source to form interference light; the light intensity sensor is used for detecting the intensity of the interference light and generating a voltage signal with a linear relation with the intensity of the interference light; the data acquisition device is used for converting the voltage signal into a digital signal; the data processing device is used for comparing the wavelength of the light source, parameters of the interferometer and data corresponding to the acquired digital signal with calibration data to obtain components and content of the gas to be detected.