The invention relates to a process for treating low-concentration DMF wastewater by a double-effect rectification method with a heat pump. With adopting of a reduced pressure flash evaporation technology, the concentration of DMF is effectively improved, and thus energy consumption in a dehydration process is reduced. A tower kettle material after flash evaporation is heated and pressurized and then goes into a reduced pressure rectification tower for separation. Heat of the tower top of the reduced pressure rectification tower is used for providing a heat source for a tower kettle material of a flash evaporation tower, and a tower kettle material of the reduced pressure rectification tower is used for providing a cold source for tower top condensation of the flash evaporation tower through a compressor. The process effectively reduces the energy consumption quantity in the DMF recovery process, and is especially suitable for treating the low-concentration DMF wastewater (with the DMF mass concentration of less than or equal to 40%); and the yield can reach up to 99.9%.