A continuous process was employed to improve the volumetric productivity of bioethanol production from NaOH pretreated barley straw using twin-screw extruder reactor.After pretreated biomass was washed and dewatered, it was used directly in a simultaneous saccharification and fermentation (SSF) process with a biomass feeding system continuously.A fermentor consisting of two linked stirrer tanks was used for SSF process.Pretreated biomass was put 100g / h for reasonable residence time.Also cellulase was added 30FPU g / cellulose as biomass feeding rate by pump and pH was adjusted 5 with acid.We chose the dilution rate on the basis of the highest volumetric productivity and ethanol yield were observed at a dilution rate of 0.0167 h-1.The volumetric productivity, final ethanol concentration, and % of theoretical ethanol yield were 1.29 g/L h, 77.3 g/L, and 90.0%, respectively.This study has a great significance that bioethanol was produced from lignocellulosic biomass continuously.