This experiment was conducted to evaluate the effect of ensiling on fermentation quality and aerobic stability of a total mixed ration (TMR) containing wet brewers’ grains and corn straw. During the ensiling period, pH fell dramatically from 6.00 to 3.92 at the initial 3 days, then it maintained relatively stable. Lactic acid concentration firstly increased rapidly then it became slowly to reach 3.21% at day 28 post-ensiling. No propionic acid or butyric acid was observed throughout the ensiling. When exposed to air, the temperature of TMR increased quickly to reach a maximum of about 45°C at the 6-day, then it tended to decline until day 9. Later, it had another relative low peak at the 10-day, then it dropped slowly to be equal to air temperature. For TMR silage, no heat production or mold were detected in the entire period. In addition, during the days of exposure, the pH for TMR varied from 6.0-8.7, while TMR silages had no significant differences (3.86 to 3.87). The number of lactic acid bacteria (LAB) for the TMR decreased from the initial 3.2×103 cfu g-1 to below detectable levels and yeast counts increased by 1000 times. However, the TMR silage had no significant change in LAB and yeast counts. These results indicated that the TMR silage showed great quality and aerobic stability. Overall, fermentation plays an important part in helping total mixed ration silage forming a good aerobic stability.