Starch gel electrophoresis was used to examine the banding pattern of Esterase isozyme in the leaf, root-nodule and seedling of four wild legume species, Trifolim repense, Glycine soja, Phaseolus nipponensis and Vigna uexillata. The number of band, enzyme activity and migrating rate of esterase isozyme varies depending on the species and tissues of legume plants. The isozyme banding pattern in the cotyledon and radicle of T. repense showed same pattern, however, the number of band were varible among the cotyledon of G. soja, P. nipponensis and V. vexzllata, respectively. Est-1 in the leaf of G. soja, V, vexillata. root-nodule of G. soja and seedling of V. vexillata expreesed the highest enzyme activity. The Est-1 showed the rapidest migrating rate among the isozymes.