An atomic force microscopy（AFM） probe based corona discharge sampling device for desorption ionization in scanning probe microscope mass spectrometer（SPM-MS） is put forward.Through finite element analysis

research is done on the mechanical and electrical character of the AFM probe tip.Electrical analysis shows that the field intensity around the AFM probe could achieve 0.32～62.4V/μm when the gap distance is 100 μm and the applied voltage is 1 kV

validating the feasibility and usability of the sampling device.The relationship between discharge current I and applied voltage V is studied through corona discharge experiment.These works lay a foundation for developing the corona discharge for non-contact sampling based on AFM probe.