Abstract： Objective Observation and Study of Killing and Proapoptotic Effects of Topoisomerase Ⅰ (topotecan) inhibitor on L1210/CDDP cells. Methods Analyze Topotecan' s killing activity and inductive effect on L1210/CDDP cell lines and the relationship between the above two and Caspase, using MTF method,Annexin V FITC staining, DNA ladder electrophoresis and cell morphology methods. Results TPT on L1210/CDDP cell line has strong anti-role, and a clear time-dependence. At the same time, the target cells present a sign of apoptosis. Caspase-specific inhibitor can cause a certain effect on apoptosis. Conclusion Topotecan' s killing activity and inductive effect on L1210/CDDP cell lines can result in activation of Caspase-8 and Caspase-3.