Objective:To investigate whether or not caffine can improve cisplatin-induced apoptosis in vitro,to offer experimental basis about clinic chemotherapy of osteosarcoma by caffine.Methods:Osteosarcoma cell(OS-732) were cultured with caffine,cisplatin or caffine adding cisplatin.We called them control group,caffine group,cisplatin group and mixing group respectively.Enhancement effect of caffine in cisplatin-induced apoptosis of osteosarcoma was observed from three aspects.Results:Apoptosis were observed in three durg groups.Percentage of apoptotic cells in mixing group was higher than that's in other groups( P 0.05).Conclusions:Caffine had remarkable enhancement effect in cisplatin-induced apoptosis of osteosarcoma cell.