Objective To investigate the mechanism by which methyl pyropheophorbide-a-mediated photodynamic therapy (Mppa-PDT) inhibit cell viability and induce apoptosis in human ovarian cancer cell line SKOV3. Methods Human ovarian cancer cells SKOV3 at the logarithmic growth phase were divided into Mppa-PDT treated group (both Mppa and PDT treated group) and control groups (the blank group, the only Mppa treated group and only PDT treated group). After Mppa-PDT treatment, the cell viability was examined with CCK-8 assay; cell apoptosis was detected by flow cytometry with Annexin Ⅴ-FITC/PI; and nuclear morphological changes during cell apoptosis was detected by DAPI staning. Moreover, the celluar reactive oxygen species (ROS) were detected by DCFH-DA staining; DNA damage was observed by single cell gel electrophoresis; and the protein expression of p53, Caspase-3, Bax, and Bcl-2 were assessed by Western blotting analysis. Results (1) Mppa-PDT could greatly suppress the cell viability of human ovarian cancer cells SKOV3 in a dose-dependent manner. (2) The cell apoptosis rate of Mppa-PDT treated group was significanlty higher than those of three control groups (blank group, Mppa group and PDT group) (P<0.05), and there was no difference among the three control groups (P>0.05). (3) After treating with Mppa-PDT, DAPI staining showed strongly stained nuclei of the apoptotic cells; DCFH-DA staining displayed higher level of ROS than those of the three control groups; single cell gel electrophoresis showed greater DNA damage than those of the three control groups; and Western blotting analysis showed that the expression of p53, Caspase-3 and Bax protein was increased and Bcl-2 protein was decreased (P<0.05). Conclusion Mppa-PDT can significantly suppress cell viability and induce apoptosis in human ovarian cancer cell SKOV3, accompanied by DNA damage and the activation of mitochondrial apoptosis pathway.