Abstract: This study aimed to evaluate and compare the improving effect of Tibetan local lactic acid bacteria and commercial lactic acid bacteria preparation on the silage fermentation quality of Vicia sativa. The experiment consisted of 5 treatment groups with 3 replicates in each group, including a control group （C, no supplementation）, a supplementation group of commercial lactic acid bacteria preparation （G）, and 3 supplementation groups of local lactic acid bacteria （supplementation of Tibetan local lactic acid bacteria HG24, LMG4 and LOG5, respectively）. At the 60th day of silaging, the silage samples from different groups were collected and their fermentation quality, nutritive value and microbial composition were determined. The results showed that compared with the control group, the lactic acid bacteria supplementation groups （G, HG24, LMG4 and LOG5） had higher lactic acid content and lactic acid bacteria count, lower pH value and ammonia nitrogen/total nitrogen value, trace content of butyric acid, and good fermentation quality; the lactic acid content and lactic acid/acetic acid value of LMG4 and LOG5 groups were significantly higher than those of the other groups （P〈0.05）, while the pH value, acetic acid content, total volatile fatty acid content and ammonia nitrogen/total nitrogen value were significantly lower than those of the other groups （P〈0.05）; the content of lactic acid and lactic acid/acetic acid value of HG24 group were significantly higher than those of control group and G group （P〈0.05）, while pH value, acetic acid content, total volatile fatty acid content, ammonia nitrogen/total nitrogen value were significantly lower than those of control group and G group （P〈0.05）. In conclusion, the improving effect of silage fermentation quality of Vicia sativa was LMG4 group, LOG5 group 〉 HG24 group 〉 G group 〉 control group.