Abstract: The vacuum electronic device has gone through more than a hundred years since its birth and has had a profound impact on promoting the development of information technology. But since the middle of the 20th century, semiconductor devices have gradually replaced vacuum electronic devices in many application fields by virtue of their excellent performance such as miniaturization, integration and low cost, and have made remarkable achievements. However, as Moore's law is approaching its limitation, semiconductor devices and chips have been faced with many serious problems such as short-channel effect, gate leakage increase and quantum effect, and the development of new transistor architectures is imperative. In fact, vacuum is the most ideal medium for electron transport because there is no lattice collision and energy dissipation, and the electron saturation speed is close to the speed of light. Therefore, in recent years, it has been proposed to combine vacuum electronic devices with semiconductor devices to form a new “micro-nano air channel transistor”. The transistor utilizes a “hollow” semiconductor electron transport channel to enable ballistic electron transport in the nanoscale air channel without scattering, thus achieving a super-fast response speed, ultra-high transport efficiency, ultra-high operating frequency, ultra-high response, as well as excellent anti-irradiation resistance to high temperatures, and can be integrated with the traditional solid-state devices. This new type of transistor has attracted wide attention at home and abroad, and has shown excellent performance in the fields of high-power picosecond switch, millimeter-wave terahertz device, and optoelectronic detection, providing new ideas for the development of devices in the post-Moore era. The working principle, domestic and international development status, typical configuration and process technology of micro-nano air channel transistors are described, and their development prospects are discussed.