Abstract: In this paper， the contents of soluble carbohydrate， soluble protein and starch were detected by anthrone colorimetry method， Coomassie Brilliant Blue method and perchlorate acidolysis anthrone colorimetry method， respectively， to investigate the plant characteristics， rules of pod dropping and development features of pod and seed of Sophora tonkinensis Gagnep. Results showed that the pod dropping number of S. tonkinensis in the mid-July to mid- August achieved the most. During the period， the pod dropping rate of whole plant was 52.07%， the main branch was 48.36%， and the flower branch on the ear was 43.97%. One pod contained 2-3 seeds and the seed number was relatively stable throughout the whole podding stage. During the mid-June to mid-July， the weight gain of fresh pod was rapid and more， the average daily gain weight was 0.0222 g. The weight gain was not obvious after the mid-July and tended to be stable. The fresh and dry weight of seed increased in the form of curve on the whole fruiting period， the length and thickness of seed in the form of a parabolic， then remained stable in September. The content of soluble sugar in seed increased to a relative high level and remained a stable tendency in the mid-September， soluble protein had the maximum in the mid-August， the content of starch increased in the form of linear in the mid-June to September.