Abstract: According to the requirements of localization of quadrupole mass spectrometer,QMS101 quadrupole mass spectrometer had been developed.The physical part of QMS101 was a 90°off-axis structure.It was designed with an axial open EI source and the quadrupole was 203.2 mm long and the field radius was 4.157 mm.It was equipped with Faraday plate and microchannel plate(MCP),in which the MCP was installed 90°off-axis.The mass range of QMS101 was 1 to 1 040 amu.Faraday and MCP were working normally under the operation of deflection electrode.Simulation of ion trajectories from quadrupole mass filter outlet to MCP surface and experimental of MCP gain attenuation show that the application of MCP in quadrupole mass spectrometer should match the ion focusing and collection area.The physical part of QMS101 can be used as a general quadrupole mass spectrometer analyzer.Equipped with different RF power supplies,it can cover most application requirements of quadrupole mass spectrometer.