Objectives : The present study was carried out to investigate the effects of Astragali radix on the asthma treatment. EAR-I is an extract of astragali radix cultured for one year and EAR-III is an extract of astragali radix cultured for three years. Methods : Two asthma-induced groups mice group was treated respectively with EAR- I and EAR- III. The other group was not. Each group was analyzed in vivo and in vitro experiments. Results : In asthma-induced mice by OVA treatment, the weight of lung, total cell number of leukocyte and eosinophil in BALF, both EAR- I and EAR- III treated groups were significantly decreased compared to control group. IL-4, IL-5, IL-13, histamine, IgE in BLAF of group treated with both EAR-I and EM-III were significantly decreased compared to control group. In FACS analyzing, granulocytes, $CD3e^-$/$CCR3^+$, $CD3^+$/$CD19^$, $CD3e^+$/$CD69^+$, $CD4^+$, $CD8^+$ and $GR-1^+$/$CD11b^+$ were significantly increased in asthma induced mice group by OVA treatment compared to control group, and decreased in group treated with both EAR- I and EAR-III. Conclusions : The present data proves that extract of astragali radix has an effect on the inhibiting asthma. Moreover, astragali radix cultured for three years was proved to be superior to the one cultured for one year.