Combination contamination of heavy metals is one of important soil contamination types. Phytoremediation is an effective approach for remediation of heavy metal contaminated soils. Nutrient solution culture was conducted to determine the effect of Pb and Zn contamination singly or in combination on the chlorophyll content and antioxidant enzyme activities of Houttuynia cordata Thunb. In single-heavy-metal systems, as Pb concentration varied from 5 to 400 mg/L in the nutrient solution, total chlorophyll content in leaves decreased linearly by up to 40%. As Zn concentration varied from 0 to 50 mg/L in the similar single-heavy-metal systems, the total chlorophyll content in leaves increased initially and then decreased as the Zn concentration in the culture increased beyond 10 mg/L. The activities of SOD, POD and CAT in those single heavy metal systems increased with Pb concentration initially to pass a maximum and declined as the Pb concentrations exceeded 100 mg/L. For the effects of Zn concentrations on the enzyme activities in similar systems, the same trends were found for SOD and CAT, but not for POD. Instead, the activity of POD increased with the Zn concentration in the entire tested range.In the dual heavy metal systems, Pb-Zn interactions increased chlorophyll content of Houttuynia cordata Thunb, restrained the activities of SOD and POD, but has no significant effect on the activity of CAT. These results indicated that the effects of single Pb and single Zn treatment on chlorophyll content and antioxidant enzyme systems were more severe than the combination effects of Pb-Zn interactions. In addition, the The high Zn concentration resulted in obvious damage of Houttuynia cordata Thunb. In contrast, Houttuynia cordata Thunb could normally grow with high Pb concentration up to 400mg/L. Therefore, Houttuynia cordata Thunb may have a high tolerance to Pb.