Abstract: As an efficient and sensitive mass spectrometry instrument, the quadrupole mass spectrometer is widely used in material composition analysis. Currently, there is relatively less research on large mass number quadrupole mass spectrometers. In this paper, we establish the physical model and electric field model of a large mass number quadrupole mass spectrometer using COMSOL simulation software. We simulate and analyze the effects of changes in lens voltage from the ion source, AC field frequency, detector deflection voltage, and secondary electron multiplier voltage on ion transmission efficiency. To improve transmission efficiency, it is necessary to minimize the flight time of charged ions in the quadrupole electric field and ensure that the incident angle is concentrated and perpendicular. Based on the optimal parameters from the simulation results, we have achieved independent research and development of a large mass number quadrupole mass spectrometer, obtaining a mass number testing range of 1~1000 amu, with detection sensitivity reaching 10 A/Pa under the secondary electron multiplier detection mode. In the future, we can further develop parameter-specific testing modes to address issues of mass discrimination.