Abstract: In order to screen out the silage additives and the optimal addition amounts suitable for the natural grassland forage in Bashang of Hebei province, in the experiment, different levels of lactic acid bacteria（0.01 g/kg, 0.02 g/kg, 0.03 g/kg）, sucrose（0.5 g/kg, 1.0 g/kg, 1.5 g/kg, 2.0 g/kg） and cellulase + xylanase combination（12 U/g xylanase combination 1, 6 U/g cellulase +9 U/g xylanase combination 2, 12 U/g cellulase +6 U/g xylanase combination 3, 18 U/g cellulase +3 U/g xylanase combination 4, 24 U/g cellulasecombination 5） were added to the experimental forage, respectively. The experimental forage without any additives was used as the control group. Sensory evaluation was conducted after 60 days. Fermentation quality assessment, nutrient contents and relative feeding value（RFV） determination were performed. The results showed that the sensory evaluation grade of 0.02 g/kg lactic acid bacteria treatment group, 2.00 g/kg sucrose treatment group, combination 1 enzyme treatment group and combination 3 enzyme treatment group was grade 1（excellent）, which was superior to the control group（grade 2, fair）.The pH value in different levels of lactic acid bacteria treatment group was significantly lower than that in the control group（P＜0.05） and the pH value of 0.03 g/kg lactic acid bacteria treatment group were the lowest.There was no significant difference in the pH value between different levels of sucrose treatment group and the control group（P＞0.05）. Compared with the control group, the pH value in the combined enzyme treatment groups was significantly decreased（P＜0.05） except for the combination 4 enzyme treatment group（P＞0.05）, but they were significantly higher than those in 0.03 g/kg lactic acid bacteria treatment group（P＜0.05）.The ammoniacal nitrogen content in different levels of lactic acid bacteria and sucrose treatment groups was significantly lower than that in the control group（P＜0.05）. The ammoniacal nitrogen content in the combination enzyme treatment groups was significantly lower than that in the control group（P＜0.05）, except for the combination 2 enzyme treatment group（P＞0.05）.The lactic acid content in different levels of lactic acid bacteria treatment groups was significantly higher than that in the control group（P＜0.05）, and the lactic acid content of 0.03 g/kg lactic acid bacteria treatment group was the highest.There was no significant difference in lactic acid content between different sucrose treatment groups and the control group（P＞0.05）.The lactic acid content in different combinations of enzyme treatment groups was significantly higher than that in the control group（P＜0.05）, but lactic acid content in these treatment groups was significantly lower than that in 0.03 g/kg lactic acid bacteria treatment group（P＜0.05）.The content of acetic acid in different levels of lactic acid bacteria treatment group was significantly lower than that in the control group（P＜0.05）. Acetic acid content in the 1.50 g/kg sucrose treatment group was significantly higher than that in the control group（P＜0.05）, but there was no significant difference between other sucrose treatment groups and the control group（P＞0.05）.The acetic acid content in the combined enzyme treatment groups was significantly higher than that in the control group（P＜0.05） except for the combination 4 enzyme treatment group（P＞0.05）. Propionic acid was not detected in the control group, different levels of lactic acid bacteria treatment group, different levels of sucrose treatment group, combination 3 and 4 enzyme treatment groups.No butyric acid was detected in the control group, 0.02 g/kg lactic acid bacteria treatment group, 0.03 g/kg lactic acid bacteria treatment group, different levels of sucrose treatment group and combination 5 enzyme treatment group.The content of DM, EE, CP and NDP in all treatment groups was not significantly different from that in control group（P＞0.05）.Ash content in the combination 1 enzyme treatment group was significantly higher than that in the control group（P＜0.05）.The WSC content in 0.03 g/kg lactic acid bacteria group and combination 2 enzyme treatment group was significantly lower than that in the control group（P＜0.05）.The ADF content in combination enzyme treatment group 2 was significantly lower than that in control group（P＜0.05）, and RFV was significantly higher than that of control group（P＜0.05）. Therefore, adding lactic acid bacteria, sucrose or cellulase + xylanase could improve the silage quality in different degrees, and adding 0.03 g/kg lactic acid bacteria had the best effect. Adding 6 U/g cellulase +9 U/g xylanase could effectively improve the nutritional quality of silage.