Mechanical vapor recompression (MVR) system has been more and more popular because of its good energy-saving effect and small footprint, but how to make the stability and energy-saving of whole MVR evaporation system are better still need to further research on its performance. With the help of Aspen Plus software version, the MVR performance analysis model was set according to the operation principle of MVR to study the relationship between the amount of evaporation, the amount of fresh steam and feed temperature, evaporation pressure, and the relationship between evaporation and boiling temperature and feed concentration (NaCl mass fraction) and evaporation pressure, the relationship between heat transfer rate of evaporator, COP and evaporation pressure, pressure increase of compressor by changing the parameters of MVR node. Make conclusions by analyzing the simulation results: the COP can be improved by reducing the compression ratio properly; the feed should be heated to the boiling point temperature and then into the evaporator for heat transfer; MVR evaporation system is more suitable for operation at low temperature and low pressure from the view of energy saving; the feed with high concentration should be dilute before evaporation.