Changing climate could be effect on the growth of soybean and seed yield, so we evaluated newly developed soy cultivars in the point of the physiological characteristics by changing temperature and light intensity in the phytotron. Two soy cultivars evaluated in three temperature levels (T1, 20/15; T2, 25/20; T3, 30/25oC at day/night) the pot experiment in phytotron between winter and spring in 2006 and spring and summer in 2007. Increased temperature from T1 to T2 and T2 to T3 enhanced crop growth parameters greatly and shortened growth duration and increased seed yield, however, grown in winter and spring enhanced too much plant height, so plant stems were very slim and weak and it resulted in the lodging problem. In this results we can estimate warming in Korean peninsular which might be increase temperature with low light intensity, so plant breeders and physiologists should be develop improved lodging resistance cultivars under low light intensity and high temperature.