Abstract： Objective To evaluate the genotoxicity of a magnesium alloy coated with β-tricalcium phosphate(β-TCP).Methods Four groups were designed.In the first group,AZ31B magnesium alloy surface was coated with β-TCP using chemical bath deposition,and in the second group magnesium alloy was tested.The other two groups were negative control(pure titanium)and positive control groups(0.5 mg/L bleomycin).Single cell gel electrophoresis was adopted to investigate genotoxicity of the alloy samples in different groups,and 60 cells from each group were analysed.Tail moment and tail DNA percentage were used as reliable indicators to show DNA damage in lymphocytes induced by every testing sample.Student-Newman-Keuls(SNK)test wag used to compare results from 4 groups.Results There were no significant differences in tail moment and tail DNA percentage between magnesium alloy group[(0.52±0.12),(6.82±1.81)%]and magnesium alloy coated with β-TCP group[(0.51±0.12),(6.89±1.93)%,P＞0.05].Tail moment and tail DNA percentage in negative group were(0.47±0.14)and(6.29±1.64)%,and tail moment and tail DNA percentage in positive group were(5.17±1.23)and(22.09±4.51)%.Conclusions No significant increase was found in DNA damage in lymphocytes induced by magnesium alloy coated with β-TCP.