This experiment was carried out to examine ecological response and soybean quality as affected by environmental cultivation for producing high seed quality in domestic soybean variety. The results are as follows: Under equal cumulative temperature condition, soybean plants grown in Muju showed longer days to flowering, which was an effect of the long day-length on high latitudes, and longer duration of reproductive stage as a result of low temperature within that period. Considering apparent seed quality, 100 seed weight of soybeans grown in Muju was heavier than Miryang. Ratio of seed crack and disease-damaged seeds was lower in Muju, and these parameters decreases as planting was delayed. The protein contents did not show significant difference in terms of altitude and planting date, however, crude oil contents were higher in Miryang. An opposite trend was observed in C18:1 and C18:3. In the fatty acid composition, the proportion of C18:1 decreased as seeding date was delayed, and was higher in Miryang. Opposite observations were obtained from C18:3. The anthocyanin contents were highest on June 10 planting and higher in Muju than in Miryang. Isoflavone content was higher as seeding date was delayed and is similar accross seeding dates in Muju. As a summary, for high seed quality production the optimum planting date was June 10, and Muju was more suitable region than Miryang.