Two varieties of Vicia sativa L. with different Cd tolerances (Cdtolerant variety L3, Cdsensitive variety ZM) were studied to compare concentrations of ascorbic acid (AsA), activities of dehydroascorbate reductase (DHAR) isoenzymes and ascorbate peroxidase (APX) isoenzymes, and APX gene expression in response to Cd treatment in the roots. Results showed that: (1) Cd treatment significantly increased the concentrations of AsA and dehydroascorbate (DHA) in the roots of both L3 and ZM. Cd treatment also tended to increase ratio of AsA/DHA in L3, but to decrease the ratio in ZM. At the same Cd treatment, L3 roots had higher AsA concentration and AsA/DHA ratio than that of ZM. (2) Four isoforms of DHAR were obtained in L3 and ZM roots by native PAGE and their activities generally increased with increasing Cd concentration. DHAR1 was obtained only in L3 and DHAR4 only in ZM. At equivalent Cd concentrations, the total activity of DHAR was higher in roots of L3 than that in ZM. (3) Eleven APX isoforms were obtained in both L3 and ZM roots by native PAGE. APX1, 2, 4 were induced by Cd treatment only in ZM and the activity of APX8 was more significantly induced in L3 than that in ZM. An APX gene was cloned and subjected to RTPCR analysis. The gene expression level was upregulated under Cd stress in the roots of both varieties. These results suggested that concentration of AsA, activities of DHAR and APX, and APX gene expression level increased in response to cadmium stress in the roots of two V. sativa varieties. It is possible that the more effective AsA recycle in the roots of L3 contributed to its higher AsA concentration than that in ZM, and this could be related to its stronger protection from ROS generation and finally contributed to its higher tolerance to Cd stress.