Loss of hemicellulose and inability to effectively decrystallize cellulose, result in low yield and high cost of sugars derived from biomass. In this work, dilute sulfuric acid pretreatment could easily remove most of hemicellulose as sugars. The sugars were successfully used for 2,3-butanediol production with relative high yield (36.1%). Then, the remained solid residue after acid-pretreatment was further pretreated by ionic liquid (IL) to decrease its crystallinity for subsequent enzymatic saccharification. The combination of dilute acid- and IL-pretreatments resulted in significant higher glucose yield (95.5%) in enzymatic saccharification, which was more effective than using dilute acid- or IL-pretreatment alone. This strategy seems a promising route to achieve high yield of sugars from both hemicellulose and cellulose for biorefinery.