Abstract: According to the working principle,the development of the vacuum electronic devices is divided into three stages in its 100 years history, which are:original electronic tubes with electrostatic control electrodes,microwave vacuum electronic devices working in the dynamic control mode and novel devices based on the relativistic effects. The representative devices of each stage have played an important role in their application field. With the development of electromagnetic spectrum utilization, the technical level of microwave vacuum electronic devices is developing towards the trend of high frequency, high power and high efficiency, which promotes the development of military equipment and the continuous expansion of industrial applications,especially in the field of spaceflight. In this paper, the technical developments and equipment applications of microwave vacuum electronic devices in the band of centimeter wave, millimeter wave and THz are described and the development trend of the devices is discussed.