To explore the role and possible mechanism of apoptosis and caspase-3 activity in the development of multicellular drug resistance of ovary cancer. Ovarian cancer cell A2780 multicellular spheroids (MCS) were obtained from three-dimensional culture. Drug sensitivity of monolayer cells (MC) and MCS were respectively tested by MTT staining and cytometry. The apoptosis of MC and MCS were determined by the flow cytometry (FCM). The expression of bcl-2 and caspase-3 in A2780/MC and A2780/MCS were detected by using Western blot and caspase-3 assay kit. A2780/MC was compacted into mass after 2 days in three-dimensional cell culture model, and MCS had more than two layers of cells growing within 5 days. Compared with A2780/MC, A2780/MCS were more resistant to the anticancer drug, and the apoptosis rate was significantly lower than those of A2780/MC. The activity of caspase-3 in A2780/MCS was significantly lower than the A2780/MC.But the expression of bcl-2 in A2780/MCS was significantly higher than that in A2780/MC. It was suggested that the drug resistance of MCS might be associated with the overexpression of anti-apoptosis protein bcl-2 and the down-regulation of caspase-3 activity.