TECHNOLOGY FOCUS - POLYMERS - Preferred Method: The step (b) comprises (a1) primarily separating the concentrated solution by phase separation process which is divided into the first level organic phase material liquid and water phase material liquid, (b1) entering obtained water phase material liquid into the secondary alcohol pervaporation membrane system for separating the concentrated solution by phase separation process which is divided into second level organic phase material liquid and water phase material liquid, and (c1) entering the organic phase material liquid and the second level organic phase material liquid into permeable pervaporation membrane system for dehydrating and concentrating to obtain alcohol concentrated liquid. The method further comprises separating and removing butanol fermentation liquid solid by micro-filtration device (2). The step (a) comprises carrying out batch fermentation in a fermentation tank, feed-batch fermentation and continuous fermentation. In the continuous fed-batch fermentation process, the mass fraction of butanol extracted from the fermentation tank is 0.5-0.9%. Preferred Components: The primary pervaporation membrane in the system is octamethylcyclotetrasiloxane, tetramethyl tetravinyl cyclotetrasiloxane, hydroxy-terminated polydimethylsiloxane, vinyl terminated polydimethylsiloxane, poly trimethyl silicon propyne, polypropylene, polystyrene, polyvinylidene fluoride, polytetrafluoroethylene, or cellulose and its modified material. The secondary pervaporation water permeable membrane in the system is polyvinyl alcohol, polyacrylonitrile, polyacrylic acid, polyamide, polyimide, high molecular ionomer, chitosan, alginate acid, or acetic acid cellulose and its modified material. The micro-filtration membrane in the micro-filtration separation device is cellulose, cellulose acetate, polyethylene, polypropylene, polystyrene, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, polyester, polysulfone, nylon, zirconium oxide, titanium oxide, or aluminum oxide and its modified material. The butanol fermentation liquid alcohol is present in an amount of 0.5-1.4%.