To develop potent and selective anticancer agents, a series of novel 4-substituted 1,2-bis (4-chlorophenyl)-pyrazolidine-3,5-dione derivatives were designed and synthesized. All the compounds were evaluated for their antiproliferative activities against a panel of four human cancer cell lines. Among them, compound 4u is the most potent, exhibiting IC50 values ranging from 5.1 to 10.1 µM, respectively. Flow cytometry analysis and western blot analysis revealed that treatment of compound 4u inducing MGC-803 cells cellular early apoptosis via activation of caspases-9/3. Furthermore, compound 4u effectively reduced the tumor growth bared by human gastric cancer cells in vivo without obvious adverse side effects. Our findings indicate that compound 4u may serve as a leading compound to target solid tumors.