The present disclosure discloses a microwave flash evaporation process and apparatus and uses thereof. A microwave flash evaporation process, wherein the process makes integration of those technologies for liquid spraying, liquid droplet flash evaporation, microwave enhancement, vacuum steam discharge, and simulation and optimization of multi-mode resonant cavity, wherein through the coupling effect of the microwave, by means of one stage microwave flash evaporation, the effect normally achieved by multi-effect evaporation and flash evaporation is obtained and a liquid droplet micro-system with microwave energy transfer in situ is formed so as to prevent a circulation pump and a steam heat exchange system from being corroded under high temperature and high pressure, and prevent scaling on a heat exchanger, and improve evaporation efficiency. The present disclosure makes integration of those technologies for liquid spraying, liquid droplet flash evaporation, microwave enhancement, vacuum steam discharge, and simulation and optimization of multi-mode resonant cavity, and can be used for performing the processes of effluent disposal, seawater desalination, evaporation concentration of spent liquor of Bayer process, concentration crystallization of chemical production, sterilization of solution, unoil of solution, the rectification separation for various organic mixed solutions, sterilization, unoil and dehydration of solid powder. There is a prospect for this new process of the present disclosure with short technological process to upgrade the evaporation process.