Abstract: The effects of adding pre-fermented juice of epiphytic lactic acid bacteria (FJLB), lactic acid bacteria (LAB) and glucose (G) on fermentation quality of napier grass (Pennisetum purpureum) were evaluated. The treatments were control (without additives), FJLB, LAB, G, FJLB+G, and LAB+G. The silos were opened on 3, 7, 14, and 30 days after ensiling and the fermentation quality was analysed. Compared with the control, LAB addition had no significant effect on fermentation quality, while FJLB addition reduced fermentation quality In the FJLB addition treatment, lactic acid and water soluble carbohydrate decreased significantly (P<0.05) while pH, ammonia nitrogen, acetic acid and butyric acid increased significantly (P<0.05). In the G, LAB+G, and FJLB+G addition treatments, lactic acid content increased significantly (P<0.05) at an early stage of ensiling, maintaining a high lactic acid/acetic acid value throughout the fermentation process. pH and ammonia nitrogen content of the final silages decreased significantly (P<0.05), but with no significant difference between the three treatments. In conclusion, glucose addition was more important and efficient in stimulating homofermenter activity and in improving the fermentation quality of napier grass silage than inoculation with lactic acid bacteria (LAB or FJLB).