Abstract: The hermetic package design of T/ R module is an important means to improve the reliability of modules, thus improving the reliability of long-tern use of the phased array radar. Combined with the internal compositions in T/ R modules which are made by hermetic package, the material selection of packaging shell, structure design and packaging process are systematically analyzed and discussed in this paper. Selecting shell material matching thermal expansion coefficient of matrix ceramic material, optimizing shell structure combined with packaging and welding process design, fully and reasonably carrying out test verification are the key to solve the problem of hermetic package of modules. At the same time, examples are given to illustrate the hermetic package design of T/ R modules.