Internal atmosphere content testing device and testing method

The invention discloses an internal atmosphere content testing device and a testing method.The internal atmosphere content testing device comprises a vacuum chamber, a mass spectrometer and an ionization source, the vacuum chamber serves as a gas ionization cavity, and a gas sampling device inputs gas to be detected into a testing cavity of the vacuum chamber; the ionization source arranged in the test cavity ionizes the gas to be detected to form an ion beam, and the ion beam enters the mass spectrometer under the driving of the ionization source to detect and analyze the components and content of the gas. The testing method is used for the internal atmosphere content testing device. When the internal atmosphere content testing device is used for performing a partial atmosphere test on a small-cavity gas sealing device, a high-vacuum environment can be created in the testing cavity to perform gas component and content test on trace gas, and the gas is directly diffused in the testing cavity without conductan