Purpose: Contents of astragaloside I, II and IV, cytotoxicity, anticancer activity, immunomodulatory activity and antioxidant capacity were to be compared as a function of the cultivated years as one, three, five and seven years. Method: Major components of Astragali membranacei Radix were separated as astragaloside I, astragaloside II, astragaloside IV by HPLC analysis. Cytotoxicity and anticancer activities were measured by MTT and SRB assay. For immunomodulatory activity, the secretion of IL -6 and $TNF-{alpha}$, NK cell activation and macrophage activation were observed as well as kinetics of responding to human T cells by a microphysiometer. In vitro antioxidant activities were measured by several radical scavenging activities of superoxide anion radican, DPPH, LDL and linoleic acid. For in vivo activity, the activation of SOD, GSH-px, catalase, ALDH and ADH was measured as well the relative weight of liver. Result : 1. For HPLC analysis, the contents of all of astragaloside I, astragaloside II, astragaloside IV were in order of three, five, one and seven years. 2. The cytotoxicity of normal human lung cell line, HEL299 showed lower than 18% in adding 0.25 mg/ml, and 28.9% in adding 1.0 mg/ml of water extract of seven year root. For methanol extracts, three year root showed highest cytotoxicity as 35.2 % and there was no difference between the cultivated years. 3. For anticancer activities, methanol extracts of one and three year roots showed relatively high inhibition of human stomach cancer cells, AGS, breast cancer cells, MCF-7, lung cancer cells, A549 and liver cancer cell, Hep3B as well as high selectivities. 4. The water extract of seven year root could yield high secretion of IL-6 from both human Band T cells while the methanol extracts of three and five year roots secreted high amounts of IL-6 and $TNF-{alpha}$ from both Band T cells. 5. As a result of in vitro antioxidant activities, both water and methanol extracts from five and seven year roots showed high activities for superoxide anion radical scavenging activity, inhibiting linoleic acid peroxide and contents of total phenols. 6. For in vivo tests, Mn-SOD and GSH-px activities and weight of liver were better in adding seven year root. For ALDH activity one year root was better and for ADH activity five year root. Overall speaking, seven year root showed relatively better antioxidant activities. Conclusion:There was difference of the contents of astragaloside I, astragaloside II, astragaloside IV according to cultivation year. Methanol extract showed better activities of anticancer and immune activation rather than water extract Interestingly enough, for methanol extracts, overall activities were improved as the cultivation year increased. There might be further investigation required for the clinical uses of the results as several biological activities varied according to the cultivated year of Astragali membranacei Radix.