Abstract: The charge exchange reactions are of a growing importance in the gas phase chemistry and the structure determination of organic molecules, especially in the field of the study of doubly charged ions. Various kinds of mass spectrometric techaniques have been developed in the recent twenty years for the study of doubly charged ions, such as 2E, E/2, charge stripping and ECID spectrometry. In the present review the principle and application of the charge exchange reactions and the related mass spectrometric techaniques were described. The characteristics of doubly charged ions in 2E spectra, the application of charge stripping and ECID spectra in the gas phase chemistry and structural determination were discussed in detail.