In this study, eight physical and chemical pretreatments were compared in terms of their enhancements on biomass enzymatic saccharification in reed. Despite 8% NaOH pretreatment could result in 100% biomass enzymatic digestion while co-supplied with 1% Tween-80, it only produced bioethanol at 10% (% dry matter). By comparison, 10% Cab pretreatment with Tween-80 is a relatively low-cost biomass conversion with ethanol yield at 12%. Notably, the steam-explosion pretreatment with 1% Tween-80 could cause a complete biomass enzymatic hydrolysis with bioethanol yield at 17%. The sequential 5% CaO pretreatment with the steam-exploded residues could lead to the highest ethanol yield at 19% with an almost complete sugar-ethanol conversion rate. Due to much low-DP cellulose and less noncellulosic polymers (lignin, hemicelluloses) that increase biomass surfaces, the steam-exploded residues were specifically effective for Tween-80 either to block lignin absorbing with cellulases or to disassociate hemicelluloses, leading to an efficient lignocellulose enzymatic digestion. Compared with previously reported pretreatments in other C4-grasses (Miscanthus, corn, sweet sorghum, switchgrass), to our knowledge, this study has therefore provided three more applicable approaches for high ethanol production with relatively low cost, less contaminate release and efficient biomass conversion rates in reed. (C) 2016 Published by Elsevier Ltd.