Abstract: In order to define the biological characteristics of Thrips flavus（Thysanoptera: Thripidae） on soybean host plants, the detail morphological features, behavior habits and damaged symptoms were observed under the condition of artificial feeding with soybean leaves. The results showed that the metamorphosis type of T.flavus was hyperpauro metamorphosis. It had five stages（egg, nymph, pseudopupa, pupa, and adult）. There were significant differences in body color and body length between the 1^st and 2^nd instar nymph. It was mainly parthenogenetic and laid eggs on leaf tissues. Moreover, adults and nymphs mainly feed with the soybean leaves that showed an obvious diurnal rhythm. Most of them were parthenogenetic and could lay up to 23 eggs per female. Under the temperature of 25±1 ℃, it took about 16 d for the female to develop from egg to adult on soybean. The egg, nymph, pseudopupa and pupa stage was 5.73±1.66, 4.85±1.25, 1.10±0.48 and 2.67±0.71 d. The female adult longevity was 11.43±4.66 d, and the male was 13.00±7.07 d. The whole generation duration was 25.80±0.89 d. These results can provide a basis for further research on its population monitoring and control technology.