Abstract: The most prominent gap between domestic mass spectrometer and foreign products is the reliability level. In this paper, the reliability of mass spectrometer was studied from the point of view of reliability design by referring to the mature experience of reliability application in military industry. The characteristics of product life cycle was analyzed and the rule of “bathtub curve” was presented. The general composition of mass spectrometer included four basic parts: sampling and ion source module, ion transmission module, detector module, data acquisition control and upper computer module. This paper described the relationship between sub-module and system reliability, and introduced three principles of reliability design of mass spectrometer. Firstly, using mature raw materials and stereotyping technology; secondly, mastering the environment that products encounter in transportation, storage and use; thirdly, meeting the mutual requirements of manufacturing technology and debugging and testing technology. Combining with the development of inductively coupled plasma mass spectrometer, several reliability design methods were introduced, including reduction design, redundancy design, thermal design, ESD protection design, electromagnetic radiation shielding design and so on, these methods were illustrated by specific design cases. By applying reliability design principles and methods, a inductively coupled plasma mass spectrometer was developed, which is stable and reliable, and has been commercialized.