Objective:To observe the effect of compound decotion Caiyu on the immunity system of immunity hepatic damage mice.Methods:72 mice were randomly divided intonormal group,model group,control group and three therapy groups.The model of immunity heaptic damage were made by injecting BCG+LPS.ALT active unit in serum,activity of NK cell,percentage of CD+3、CD+4、CD+8 and CD+4/CD+8 of every group were determinated.Results:Percentage of CD+3、CD+4 cell and CD+4/CD+8 and activity of NK cell of three therapy groups was obviously higher than that of model group.Conclusion:Ddecoction Caiyu can strengthen the T-cell immunity function of the mice and adjust the net of the T-cell immunity,also strengthen the NK cell activity.