The objective of this experiment was to determine the ensiling characteristics, microbial changes and in vitro degradation of erect milkvetch (Astragalus adsurgens Pall.) treated with different additives. Erect milkvetch was treated with distilled water (control), inoculant (I, lactic acid bacteria), enzymes (E, fibrolytic enzymes) and inoculant + enzymes (I + E) prior to ensiling. Three bag silos were used and opened after 1, 3, 5, 15, 30 and 45 days for chemical analysis and microbial measurement. For all the silages, there was a rapid decline in pH during the first 5 days of ensiling. Compared with the control, all added treatments (I, E and I + E) resulted in higher (P<0.05) lactic acid concentration at all ensiling periods. The crude protein content was higher, and neutral detergent fibre, acid detergent fibre and sulphuric acid lignin were lower for all treatments compared with the control (P<0.05). Treatments of enzymes (E, I + E) can also significantly improve in vitro dry matter digestibility by 10.9 and 13.6% and in vitro neutral detergent fibre digestibility by 19.8 and 21.7%, respectively. Compared with the control, treatments I and I + E increased in vitro crude protein digestibility (P<0.05). These results indicated that the addition of additives can improve both erect milkvetch silage fermentation quality and in vitro digestibility to some extent.