The invention discloses a helical mass spectrometer continuous pressure-varying sampling device, comprising a cylindrical housing and a mass spectrometry system, wherein the interior of the housing isslidably provided with an inner cylinder having a helical line groove on the outer surface. The helical line groove has gradually increased cross-sectional area from a gas inlet to a gas outlet. Theouter surface of the inner cylinder closely fits with the inner wall surface of the cylindrical housing, and the central circumference on the inner wall surface of the cylindrical housing is providedwith an annular gas inlet chamber. The gas outlet of the helical line groove is equipped with a gas outlet channel that penetrates through a cylinder wall of the inner cylinder near the mass spectrometry system, and penetrates through the side wall of the housing via a pipeline to connect with the mass spectrometry system. A driving motor drives the inner cylinder to slide in the housing through ascrew mechanism. The helical mass spectrometer continuous pressure-varying sampling device has compact structure and the capability of continuously sampling the gas to be analyzed online; when the inner cylinder slides in the housing, the length of the gas channel and cross-sectional area for the helical line groove are changed, so that the helical mass spectrometer continuous pressure-varying sampling device has high-precision sampling analysis ability to a wide range of pressure-varying gas.