[Objective] To understand the influence of Qi-Wei-Bai-Zhu-San on blood of diarrheal mice with dysbacteriosis. [Methods] Diarrheal mice model with dysbacteriosis was made by feeding antibiotics, then treated with intragastric administration of Qi-Wei-Bai-Zhu-San and 1/2 amount of ultra-micro Qi-Wei-Bai-Zhu-San. The blood was collected by the eyeball method and analyzed with the CA-500 blood automatic instrument. [Results] The values of PLT (platelet), MCV (mean corpuscular volume) and WBC (white blood cell) in the model group mice were lowed than that in control group mice (P<0.01 or P<0.05). After treatment by gavage, the values of PLT, MCV and WBC of the traditional decoction group and 1/2 amount of ultra-micro Qi-Wei-Bai-Zhu-San increased, and the MCV of traditional decoction group returned to normal and had no statistical difference comparing with control group (P>0.05). There were no statistics differences in the values of PLT and MCV between ultra-micro 1/2 amount group and control group (P>0.05). It implied that the blood recovered to normal. Qi-Wei-Bai-Zhu-San could promote the production of PLT and WBC, and improve the MCV. The WBC of 1/2 amount of ultra-micro Qi-Wei-Bai-Zhu-San group increased more than that of traditional decoction group. [Conclusion] Qi-Wei-Bai-Zhu-San could control immune function of diarrheal mice with dysbacteriosis. The functions of 1/2 amount of ultra-micro Qi-Wei-Bai-Zhu-San were better than that of traditional Qi-Wei-Bai-Zhu-San.