This paper describes the research and development activities of millimetre wave and near-THz vacuum electronics in Beijing Vacuum Electronics Research Institute(BVERI)and National Key Laboratory of Science and Technology on Vacuum Electronics(NKLST-VE).These devices include TWTs,BWOs,Clinotrons and Stop-Band Oscillators etc with helix,folded waveguide and vane-loaded waveguide as high frequency interaction structures and the devices technologies mainly were composed of MEMS technology,MPCVD diamond process and metallization etc.