Abstract: The design parameters and structural components of the physical unit and circuit system of the self-developed single-focusing compact magnetic sector mass spectrometer were introduced.Its mass range,resolution and sensitivity have been calibrated.The results show that the mass range of the small mass spectrometer is 1~134 amu,the resolving power is 35,and the sensitivity of N₂,Ar and He in secondary electron multiplier(SEM)mode is 1.6×10^-4A/Pa,1.2×10^-4A/Pa and 2.3×10^-5A/Pa,respectively.The proposed compact magnetic sector mass spectrometer is widely used in the field of vacuum leak detection and mass spectrometry.