Exploring sustainable energy and chemical sources based on biomass has increased global interest. This study was focused on produce second-generation bioethanol using a new pretreatment process. The effectiveness of sodium hydroxide (NaOH) pretreatment on oil palm empty fruit bunch (OPEFB) for lignin removal, reducing sugar, and bioethanol production at low temperature and pressure was investigated using batch and continuous processes. Response surface methodology (RSM) was used to optimize the NaOH concentration and solid to liquor ratio (SL) at a maximum temperature of 100 degrees C and atmospheric pressure. The mathematical formula derived from RSM was based on 11 runs of the batch treatment. In the batch treatment process, 2 M NaOH, the temperature of 80 degrees C, and SL ratio of 8 have resulted in lignin removal of 38.7%, reducing sugars of 8.3%, and bioethanol concentration of 4.1%. The validation of formula has been calculated from calculation and experiment values. Moreover, at the same retention time, continuous pretreatment showed a reducing sugar content of 5.9% and a bioethanol concentration by 2.5%. The results show that the continuous process can be employed in effective bioethanol production from OPEFB.