Abstract: Mass spectrometer is one of the primary science payloads for deep space explorations. It has been used for the atmosphere and soil composition analysis of the planet system and the small Solar system body for many times. The composition and isotope abundant of the atmosphere and soil measurement can be used for the research of the resource prospection, inhabitability, celestial body evolvement, origin and the history of the key geologic events. Mass spectrometer has been used for several times in deep space missions of exploring the atmosphere of Mars, Saturn system, Jupiter system and comets etc. The deep space objects detected by mass spectrometer are introduced. The quadrupole mass spectrometer is used widely in deep space exploration activities. It's not only used to detect the thin atmosphere and the adsorption gas of the soil but also to detect the dense atmosphere with the front design of the vacuum equipment. The spaceborne quadrupole mass spectrometer developed by National Space Science Center has been used widely in the detection of the component and density of the Earth atmosphere. Finally, the development trends of the MS technology are analyzed, including miniaturization, broaden spectrum and large dynamic count range.