Abstract: In the present research, we established an Arabidopsis protoplast experimental system to study toxicity and DNA damage caused by heavy metals in plant cells. Protoplasts with high purity and viability isolated from mature leaves of 4-week-old Arabidopsis thaliana were used as experimental material. Three kinds of heavy metals—zinc (Zn2+), copper (Cu2+) and cadmium (Cd2+)—inducing toxicity and DNA damage in protoplasts were investigated. Cell survival rate was decreased in a time- and dosedependent fashion with the three metals. Zn2+ exposure at all concentrations induced a smaller and slower decrease in cell survival rate than with Cu2+ and Cd2+ exposure. DNA damage measured by single-cell gel electrophoresis was induced by Zn2+, Cu2+ and Cd2+ at 0.1-0.8 mmol.L-1, with significant increases in olive tail moments in all treated samples of protoplasts. As compared with Zn2+ exposure, Cu2+ and Cd2+ exposure at a similar concentration induced more severe DNA damage in protoplasts. Heavy metalinduced DNA damage was dose and time dependent. Thus, the heavy metals Cu2+ and Cd2+ are more cytotoxic and genotoxic than Zn2+. Use of single-cell gel electrophores is in the Arabidopsis protoplast experimental system is a fast and sensitive method for detecting genotoxicity caused by heavy metals.