Ethanol has been widely used as an alternative to fossil fuels. In recent years, much attention has been devoted to ethanol production from lignocellulosic biomass. In previous research, low-moisture anhydrous ammonia (LMAA) pretreatment was investigated due to its high efficiency and less washing compared to other pretreatment methods. The purpose of this study was to determine optimal conditions resulting in highest glucose yield and lowest ammonia input using the LMAA processing. In this experiment corn stover was used with different moisture contents (20, 50, 80 wb %) and particle sizes (<0.09, 0.09-2, >2 mm). Corn stover was ammoniated with a loading rate of 0.1g NH₃ /g biomass. Ammoniated corn stover then was subjected to different pretreatment times (24, 72,144 h). After that, compositional analysis, including ash content, moisture content, structural carbohydrates and lignin in biomass, and enzymatic digestibility were used to determine the glucose yield. This study focused on designing a pretreatment method which could improve the efficiency of pretreatment processing.