Abstract: With the advancement of science and technology in our country and the development of technology, the gas composition in the closed environment of special projects needs to be accurately detected. In addition to the gas composition of small m/z (within 200 amu), the detected object also contains important organic large m/z components; one of the most effective gas detection instruments for components is the quadrupole mass spectrometer. Most of the research and development institutions of mass spectrometers in China focus on the design and production of low m/z products. There are seldom reports on the design of quadrupole mass spectrometers that can measure large m/z (up to 1000 amu). In this article, mechanical parameters such as rod length, field radius, entrance aperture, and assembly precision of the quadrupole mass spectrometer are designed, as well as electrical parameters such as RF voltage and DC voltage, ion pass rate, resolution of the mass spectrometer and other index parameters were simulated and calculated, and a measurable large mass quadrupole mass spectrometer with a mass detection line up to 1000 amu was designed, which can meet the application requirements of confined spaces in special fields.