Objective To investigate the effects of a novel ruthenium(Ⅱ) polypyridyl complex △-[Ru (phen)2MCMIP]2 + (△-1) on proliferation and apoptosis of human osteosarcoma cell line MG-63 in vitro.Methods Cell counting of kit-8 (CCK-8) assay was used to detect the proliferation of MG-63 cells after 24,48,72h treatment with △-1 under the concentrations of 0.00,12.50,25.00,50.00,100.00,150.00 μmol/L;Changes of apoptosis and cell cycle in MG-63 cells after 24 h treatment of 0.00,25.00,50.00,100.00 μmol/L A-1 were determined and analyzed by flow cytometry (FCM).Results Ruthenium (Ⅱ) polypyridyl complex A-1 could significantly inhibit the growth of MG-63 in a dose and time dependent manner; the IC50 of 24 h,48 h,72 h was 57.80μmol/L,45.27μmol/L,32.51μmol/L respectively; flow cytometry detection showed that A-1 induced 37.10％ of apoptosis,while only 1.06％ in control group,and arrested cell cycle at G0/G1 phase.Conclusion Ruthenium(Ⅱ) polypyridyl complex A-1 is able to inhibit proliferation and induce apoptosis in MG-63 cells and arrest cell cycle at G0/G1 phase.