Soybean [Glycjne max Merr. L.] variety 'Danyeobkong' was inoculated with soybean mosaic virus SMV-G5H strain in field and green house at Crop Experiment Station in 1995. The effects of this virus strain on plant characteristics and seed chemical composition of the soybean variety Danyeobkong were evaluated. Yield, the number of pod and 100 seed weight were significantly reduced by SMV-G5H strain infection. Inoculation of SMV-G5H strain of soybean mosaic virus caused the increment of seed protein content and the decrement of seed oil content in the soybean variety Danyeobkong. Changing pattern of fatty acid composition by SMV-G5H strain infection was varied according to the experimental place. In field trial, the percentage of linoleic and linolenic acids decreased and stearic and oleic acids increased in the seed oil from virus infected plants. In green house trial, however, linolenic and oleic acids were increased, whereas palmitic and linoleic acids were reduced.