Abstract: Vacuum electronics is a branch of science which studies the related physical phenomena of electrons in vacuum,mainly on the generation, movement, and the interaction with the material. It is the basis of the vacuum devices, vacuum instruments and particle accelerators. Microwave vacuum electron device are the most important vacuum devices for military and civil microwave electron system, and have been widly used in the defence, national economy and scientific research. The hidtory, the stae art and developmemt of vacuum electronics and microwave vacuum electron devices will be introduced in this paper. Also the future reseach work on this research area will be discussed.