Methods: 254 AECOPD inpatients will be recruited in 6 hospitals in China over 2 years. They will be randomly assigned to Experimental group and Placebo group，Experimental: Xuebijing injection 50ml in 100ml of Normal Saline IV, in 80mins, per 12 hours. administration of the agent for consecutive 5 days；Placebo Comparator: Normal Saline 150ml IV, in 80mins, per 12 hours. administration of the agent for consecutive 5 days. Compare the following index between the two groups: Invasive mechanical ventilation rate, length of hospital stay, Treg cell,Th1,Th2,HLA-DR,CRP,PCT,IL-4,IL-6,IL-10,TNF-α，IFN-γ, APACHEⅡ, CAPS score.