Abstract: Objective To investigate the therapeutic effects of Docetaxel microspheres (D-MS), a new antitumor drug dosage form, on peritoneal metastatic carcinoma. Methods Two hundred and twenty BDF1 mice were divided into 11 groups, receiving intraperitoneal inoculation with B-16 PC melanoma for 4 days, until peritoneal metastatic carcinoma was formed. Docetaxel was administered with different formulations and doses. Average survival time was analyzed by chi-square test. Results D-MS extended the survival of mice with increasing dose of docetaxel. The average survival time of 100 and 400 mg/kg group were 28.9 and 114 days. While no significant effect was on aqueous solution of docetaxel group, as the average survival time of 100 and 200 mg/kg group were 28 and 29 days. Conclusion D-MS could be used as a new antitumor drug dosage form in the treatment of peritoneal metastatic carcinoma.