A novel stepwise pretreatment on corn stalk (CS) by alkali deacetylation combined with liquid hot water (LHW) was investigated to enhance enzymatic hydrolysis. After deacetylated treatment, strength of alkali deacetylation of CS was from 1.79% to 91.34% which was subsequently pretreated by LHW with severity from 3.27 to 4.27. It was found that higher strength of alkali deacetylation could reduce both the degradation of hemicellulose and inhibitors formation in liquid hot water pretreatment (LHWP). Enzymatic hydrolysis efficiency was confirmed to be affected by LHW pretreatment severity (PS) and strength of alkali treatment. This combined pretreatment of alkali deacetylation and LHW could not only increase glucose yield, but also enhance energy utilization efficiency. The maximum enzymatic hydrolysis of 87.55% +/- 3.64 with the ratio of glucose yield to energy input at 50.39 g glucose kJ(-1) was obtained when strength of alkali deacetylation at 84.96% with PS at 3.97 were used. (C) 2016 Elsevier Ltd. All rights reserved.