Liquid hot water (LHW) and alkali-promoted LHW pretreatments of wheat straw were comparatively studied at temperatures from 100 °C to 180 °C to investigate their ethanol production and pentose recovery. An amount of 4.52 g/L ethanol was obtained by fermentation from the synergistic substrate treated with LHW under optimal temperature (140 ºC) and enzymatic hydrolysis (EH). Under these conditions, the recovery rate of pentose was 48.8% and 58.1% for xylose and arabinose, respectively. After the pretreatment and bioconversion processes, 20.3% cellulose, 10.5% xylan, and 19.5% lignin remained solid. The alkali promoter introduced into LHW enhanced the bioconversion efficiency of the substrate, which resulted in 5.82 g/L ethanol, and 57.5% xylose and 59.0% arabinose recovery, respectively. The results from this study contributed an effective manner for co-production of ethanol and pentose, enlarging the utilization efficiency of carbohydrates.