Phenothiazine (Pht) derivatives are an active compounds which have activity in inhibiting the caspase-3 enzyme in vitro. Docking simulation was done to determine and visualize the interaction of the 9 compounds with the caspase-3 enzyme. The results of docking simulations showed that four compounds can interact spontaneously with the caspase-3 enzyme. On the caspase-3 enzyme, interact most easily through the formation of hydrogen bonds with Arg286. On the ID10a compound interact most easily through the formation of two hydrogen bonds with Ser219 and Arg269. With the inhibitory effect on the enzyme caspase-3means preventing the cancer, indicating that the four compounds studied can be applied as anti-cancer agents.