Abstract: The aim of this study was to evaluate the effects of Lactobacillus buchneri (LB) and sodium diacetate (SDA) on the fermentation quality and aerobic stability of total mixedration (TMR) silage containing wet brewers’grains in Tibet. The treatments were as follows: control (no additives), LB (at 10⁶ colony forming units/g fresh forage) and SDA (at 0.5% of fresh weight). All silos were opened after 70 days of ensiling, and a portion of silage was collected to analyze fermentation quality, and the chemical and microbial composition. A multi-channel temperature recorder was used to record the change in the temperature of the remaining silage during exposure to air, and the aerobic stability of silage samples was estimated after 6, 9 and 14 days of exposure to air. The results showed that all of the silages had good fermentation quality with high lactic acid contents, low ammonia/total nitrogen ratios, and low butyric acid contents. The addition of SDA increased the lactic acid content (P>0.05) and the dry matter recovery (P<0.05), and significantly (P<0.05) decreased the pH, ammonia/total nitrogen ratio, and butyric acid content, but did not significantly affect the crude protein content, ether extract, ash or neutral detergent fiber and acid detergent fiber contents. The addition of LB significantly (P<0.05) decreased the lactic acid content, crude protein content, and dry matter recovery, and significantly (P<0.05) increased the pH, and ammonia/total nitrogen ratio. During aerobic exposure for 14 d, the pH of all of the silages increased slowly, and the temperatures of the silages were no more 2 ℃ higher than ambient temperature, indicating that all of the TMR silages were highly stable under aerobic conditions. Treatment of the TMR silage with LB and SDA inhibited yeast and mold growth to different degrees, and improved the aerobic stability of TMR silage containing wet brewers’grains. The silage treated with SDA performed better than that treated with LB. These results indicated that adding SDA at 0.5% of fresh weight could not only improve the fermentation quality, but also the aerobic stability of TMR silage containing wet brewers’grains.