Abstract: In this paper, the straw was liquefied using glycol as solvent and enzymatically pretreated firstly. Then it was fermented by Klebsiella pneumoniae CICC 10011 to prepare 2,3-butanediol. The influence factors such as temperature, pH, inoculum, rotation speed,reaction time, substrate concentration on the liquefied products fermentation for 2,3-butanediol were studied. After double-membrane concentration of hydrolysate, the total sugar concentration of liquefied straw could be controlled between 85 and 95g/L after liquefaction and enzymolysis. This procedure not only provided enough carbon sources, but also achieved the automation of process control, increase product concentration, and reduce the cost of separation. The optimum fermentation conditions were described as follows: initial total sugar concentration was 94.3g/L; temperature was set at 37℃; pH value was 5.5; inoculation amount of strain was 10%; rotation speed was 170 r/min; fermentation was carried out for 72h. Under this condition, 36.47g/L of 2,3-butanediol was obtained with the yield of 42.5% relative to the total sugar. The efficiency was 0.51g/(L·h), and the highest yield of liquefied products which were converted to 2,3-butanediol was 33.4%.