Application of phytoremediation in the polluted area to remove undesirable materials is a complex and difficult subject without detailed investigation and experimentation. We investigated the accumulation patterns of cadmium and lead in plants naturally grown, the bioavailability of plants to accumulate these toxic metals and the responses of P. thunbergii to cadmium and lead. The soil samples contained detectable lead (＜$17.5_mu$g/g), whereas cadmium was not detected in the soils of study area. The whole body of Persicaria thunbergii contained detectable lead (＜320.$8_mu$g/g/g) but cadmium was detected only in the stem (＜7.$4_mu$g/g/g) and root (＜10.$4_mu$g/g/g) of P. thunbergii. Cadmium was not detected in Trapa japonica and Nymphoides peltata, whereas lead was detected in T. japonica (＜323.$7_mu$g/g/g) and N. peltata (＜177.$5_mu$g/g/g). Correlation coefficient between lead content in soil and in these plant samples represented positive correlation. The total content of lead in each plant sample increased in the order of N. peltata$leq$P. thunbergii<T. japonica. For the confirmation of bioaccumulation and response of plant to heavy metals, we selected P. thunbergii out of tested plant species based on field data, and P. thunbergii was exposed to cadmium and lead. The analysis of cadmium and lead in P. thunbergii and pH measurement in the culture pot of P. thunbergii were accomplished during the experiment. The contents of heavy metals in P. thunbergii treated with 10mM metals were highly detected in more quantity than those in P. thunbergii treated with 5mM metals as follows: 1.7~5.6 times in cadmium and 1.3~4.3 times in lead, respectably. The contents of lead and cadmium in P. thunbergii tended to increase, whereas the pH in cultured pot contained cadmium and lead tended to decrease throughout the experimental period. In the leaf of P. thunbergii exposed cadmium and lead, copper/zinc-superoxide dismutase (Cu/Zn-SOD) activity was elevated and catalase (CAT) activity was reduced in the presence of cadmium. Our results provided useful information for the selection of plants suitable for phytoremediation of metal-contaminated soils.