Objective To examine perfluorooctanoic acid （PFOA）-induced DNA damage using a combined in vivo and in vitro experiment.Methods Acellular nuclear DNA damage was used as a model to test the damage induced by exposure to 0.00， 0.13， 0.25， and 0.50 mmol/L PFOA for 1 h. The YAC-1 cell was used as the research model. In the cytotoxicity study， the effects of different dosages on cell activity were determined via CCK-8 assay. The final PFOA concentrations were 0， 1.0×10^-8， 1.0×10^-7， and 1.0×10^-6 mol/L. DNA damage was detected after 3 d of exposure. Rats were gavage with 0， 10， 20， 40 mg/kg·BW PFOA twice. The liver， bone marrow， and peripheral blood of rats were removed 6 h after the last administration. Alkaline and neutral comet assay were performed to measure DNA damage. The micronucleus test was performed to measure bone marrow chromosome breakage.Results Compared with the control group， acellular and cell alkaline DNA comet assay result showed that the tail DNA% of acellular nuclear DNA increased significantly in each dose group （P<0.05） within dose response relationship. The acellular and cell neutral DNA comet assay results showed no DNA breakage in each dose group （P>0.05）. The tail DNA% of each dose group in the alkaline comet assay was significantly higher than that of the control group （P<0.05）， showing a dose-response relationship. No significant difference was observed in the neutral comet assay （P>0.05）. Compared with the control group， the alkaline and neutral comet assay results showed that the tail DNA% of bone marrow， liver， and peripheral blood cells group showed no DNA breakage in each dose group （P>0.05）. Compared with the control group， the test of bone marrow micronucleus was negative （P>0.05）.Conclusion PFOA can cause DNA single-strand breakage at the subcellular level in vitro， and exposure does not induce DNA and chromosome breakage in rats after oral exposure.