The raw material meets the requirements of film inlet and enters into the preheater and evaporator through the raw material pump. After reaching a certain temperature, it enters into the membrane separation unit in the form of steam. The membrane separation unit is composed of multiple membrane components in series. The water and a small amount of organic matter in the raw materials permeate through the membrane components from the upstream side of the membrane to the downstream side of the membrane, and the final product is obtained at the upstream side of the membrane. On the downstream side of the membrane, the vapor pressure difference between the upstream and downstream components of the membrane is formed by means of vacuum extraction and condensation. The percolating liquid vapor is pumped into the condenser by the vacuum unit. The condensed osmotic fluid is discharged through the osmotic pump and recycled.