When Persicaria thunbergii and Rumex crispus were treated with Cd($NO_3$)$_2$ and Pb($NO_3$)$_2$ of 5 or 10 mM for 5 days, the amount of bioaccumulation of $Pb^{2+}$ in the leaf of P. thunbergii was 2.87-8.08$mu extrm{g}$/g and that of $Cd^{2+}$ was 0.82-2.79$mu extrm{g}$/g. In the case of P. thunbergii, the concentration of $Pb^{2+}$ in the leaf was higher than that of $Cd^{2+}$. On the other hand, in R. crispus, the concentration of $Cd^{2+}$ and $Pb^{2+}$ were similar as follows ; 1.49$mu extrm{g}$/g in $Cd^{2+}$ 5mM, 2.90$mu extrm{g}$/g in Cd2+ 10mM, 1.83$mu extrm{g}$/g in $Pb^{2+}$ 5mM and 2.73$mu extrm{g}$/g in $Pb^{2+}$ 10mM. The remaining rate of heavy metals and the variation of pH in the cultured soil decreased as compared with control (100 % and pH 6.48) after 5 days as follows; to 77.l% and pH 6.39 in $Cd^{2+}$ 5mM, 90.2% and pH 5.79 in $Cd^{2+}$ 10 mM, 81.1% and pH 6.00 in $Pb^{2+}$ 5mM, and 85.7% and pH 5.80 in $Pb^{2+}$ 10 mM. The result of size exclusion chromatography, several phytochelatins were seperated from the extract of the leaf of both plants treated with heavy metals. The molecular mass of these phytochelatins were estimated as follows; in the case of P. thunbergii, about 4,300-8,600 da by $Cd^{2+}$ and about 3,200-9,700 da by $Pb^{2+}$, and in R. crispus, about 4,300 da by $Cd^{2+}$ and about 3,200-7,500 da by $Pb^{2+}$. In addition, $A_{254}$ of these phytochelatins were higher than $A_{280}$. [Phytochelatin, Persicaria thunbergii, Rumex crispus]