The invention discloses a film sample introduction enriching device in an online gas analysis mass spectrometer, the film sample introduction enriching device comprises a film, a vacuum difference cavity body, a circulation pump, a fine tuning vacuum control valve, a tubule, a capillary, a sample inlet tube, a sample feeding valve, a sample feeding cavity, an end cover, a mechanical pump and a difference extraction opening. The film sample introduction enriching device has the advantages of good mobility, being capable of rapidly enriching samples of organic contaminants in air, realizing direct sample introduction and online enriching of samples, shortening sample responding time, dynamic balance status of the vacuum of the vacuum difference cavity body and constant degree of vacuum in the mass spectrometer during the analysis process, which is helpful to quantitative analysis, effectively reduces the adsorption and memory effect of the samples at the film surface and prolongs the service life of the film, and the enriching efficiency of the film sample introduction system can be controlled according to the test requirements.