Recently, the concern about safety and functional substances of foods are increased therefore antioxidant substances and plants which had pharmacological effect have been studied actively. It has been known that the mulberry leaf is effective in curing many diseases. Nowaday, the pharmachological effects of mulberry leaves on diabetes mellitus and their usage for many aspects were confirmed. Mulberry leaves are known for effective in prevention of diabetes mellitus, because of specific amino acids and fibers. In this study, methanol, hexane, chlorform, ethyl acetate, and butanol extracts obtained from mulberry leaves were added to soybean oil and they were stored for 30 days at $60{pm}2^{circ}C$ and peroxide value(POV) and conjugated diene value(CDV) were measured periodically. Results of this study were obtained as follows; 1. The POV of soybean oil after the addition of each mulberry leaves powder(MLP) extracts generally enhanced as the storage time was prolonged, so the POV of all samples was reached higher than 100meq./kg.oil after 10 days storage without the addition of butanol, methanol, ethylacetate, hexane extracts at 0.1% level. Especially, the POV of soybean oils including butanol extract was 87.35meq/kg.oil after 10 days storage and antioxidant activity of butanol extract was shown to be superior to that of BHT. The pattern of the changes of the CDV of soybean oil after the addition of MLP extracts at 0.02%, 0.05% and 0.1%, respectively, were almost constant during 10 days of storage and then rapidly increased during the rest of experimental periods. During 10 days of storage in case of 0.1% adding level, the antioxidant activities of the butanol extract was superior to that of the each MLP extracts.