This study was aimed to study the effects of compound lactic acid bacteria and grape seed tannins on the fermentation quality and the small intestinal absorbable amino acids of alfalfa(Medicago sativa L.) silage. Regrowth of alfalfa was harvested at the budding stage and ensiled without (control, CK) or with grape seed tannin (G), compound lactic acid bacteria (Lactobacillus pentosus + Pediococcus pentosaceus + Pediococcus lactis, L), and compound lactic acid bacteria + grape seed tannins (LG) after wilting. Silage fermentation characteristics and the small intestinal absorbable amino acids (in vitro) were determined after 60 days of ensiling. The results showed that: compared with the control group, the G and LG group had lower (P<0. 05) contents of lactic acid, acetic acid, total volatile fatty acid, and ammonia nitrogen, and the L and G group had higher (P <0. 05) content of crude protein. Compared with the other groups, the G group had higher (P<0. 05) content of He, Leu, Lys, His, Arg, Tyr, and total amino acid in silage, the yield of the rumen microbial protein, and contents of the small intestine absorbs He, Lys, His, Arg, Ser, and total amino acid. Therefore, the addition of grape seed tannins had a limited effect on improving the fermentation quality of alfalfa silage, but it increased the small intestine absorbable contents of essential amino acid Lys, His, Arg, and the total amino acid in silage.