The invention relates to a double-effect Roots-type MVR (Mechanical Vapor Recompression) falling film 
evaporation system. The double-effect Roots-type MVR falling film 
evaporation system comprises double-effect falling film evaporators and a 
water vapor recompression 
system, wherein the double-effect falling film evaporators comprise a primary-effect 
evaporator and a secondary-effect 
evaporator which respectively comprises a heating chamber and a separation chamber; the 
water vapor recompression system is mainly formed by a Roots-type MVR compressor; a vapor outlet of a separation chamber of the secondary-effect 
evaporator is connected with a vapor inlet of the 
water vapor compressor, and a vapor outlet of the water vapor compressor is connected with a vapor inlet of the primary-effect evaporator. According to the double-effect Roots-type MVR falling film 
evaporation system, by recycling low-grade 
waste heat of the primary-effect evaporator and the secondary-effect evaporator and reutilizing all 
latent heat of secondary vapor generated in a solution evaporation process, 
primary energy is saved, the 
energy consumption in a solution evaporation process is greatly reduced, and the environmental 
pollution is reduced. The double-effect Roots-type MVR falling film evaporation system is simple in structure, small in occupied space and high in 
automation degree, only requires a small amount of vapor when being started, does not require live vapor after being started, is particularly suitable for heat-sensitive materials, has a wide application range and can be used on occasions of evaporation concentration, evaporation 
crystallization and low-temperature evaporation.