The removal of solid impurities and separation of target products from a fermentation broth is becoming more tedious with the utilization of lignocelluloses as source of substrate. 2,3-Butanediol, an important chemical used widely is also a main product of sugar-based fermentation carried out by Klebsiella pneumoniae. In this study, we investigated the use of salting-out extraction (SOE) that employed a K2HPO4/ethanol system consisting of 21% ethanol and 17% K2HPO4 (mass fraction) to separate 2,3-butanediol from the viscous Jerusalem artichoke-based fermentation broth. After SOE, about 98% of solid matters was removed, and the viscosity decreased from 72.5 mPa.s in the original fermentation broth to 4.4 mPa.s in the top phase. The partition coefficient and yield of 2,3-butanediol reached 13.4 and 99%, respectively, and 89% of soluble proteins was removed from the broth. The results showed that SOE is an efficient way for isolating 2,3-BD from a highly viscous fermentation broth by removing much of the solid matters within the broth.