Abstract: Objective To study silica-induced DNA damage in human embryo lung fibroblasts(HELF)for pneumoconiosis prevention and treatment. Methods After exposed to silica,DNA double strand breaks of HELF were detected with immunofluorescence and neutral comet experiment and the micronucleus were detected with micronucleus test. Results The levels of γH2AX and Olive moments were increased significantly in dose-dependent manner after the HELF were treated with 0,100,200,and 400μg/ml silica,with the semi-quantitative values of 521.9±233.1,823.3±201.5,1375.5±311.5, and 1545.6±145.7 and 1.74±0.24%,2.67±0.36%,9.23±0.72%,and 14.16±1.05%,respectively.How ever,the micronucleus frequency was increased insignificantly compared with that of the control group. Conclusion Silica can induce DNA double strand breaks in human embryo lung fibroblasts.