Effects of molasses-alcoholic wastewater on the ensiling quality of napiergrass were investigated at ambient temperature, and its anaerobic digestion performance was assessed at mesophilic temperature. Results showed that the molasses-alcoholic wastewater had positive effect on silage quality and anaerobic digestion performance. Lower pH values of 5.20-5.28, lower NH3-N contents of 32.65-36.60 g/kg and higher lactic acid contents of 56-61 mg/kg FM were obtained for the silage samples with molasses- alcoholic wastewater addition. Higher specific biogas yield of 273 mL/g VS was obtained for the sample with 11% molasses-alcoholic wastewater added. Therefore 11% molasses-alcoholic wastewater addition was recommended. (c) 2014 Published by Elsevier Ltd.