Abstract: In this paper, the technology for the preparation of plain carboxymethyl starch microsphere (CMS-MS) was optimized by the uniform design method with CMS-Na as carrier material and p-phthaloyl chloride as acrosslinker. The carboxymethyl starch microsphere loaded mitoxantrone (DHAQ-CMS-MS) was prepared by absorption method. Then, its morphology, size and size distribution, characteristics of drug loading, drug release in vitro, preparation for clinical application and its stability were studied. The pharmacokinetics of DHAQ-CMS-MS in rabbit was also studied.The results showed that the average diameter of the DHAQ-CMS-MS was 75.71μm, drug loading was 13.21%, expansion ratio in water was 71.94%. The release of DHAQ in vitro from the microspheres was found to fit the model of single exponential function. The suspension prepared in this paper is not only convenient for clinical use, but also favorable for the improvement of the drug stability. The pharmacokinetic parameters obtained from the hepatic atery chemoembolization showed that the DHAQ-CMS-MS group, when compared with the solution group, exhibited a higher blood drug concentration in hepatic vein, its MRT was 1.96 times that of the solution group. As for the result of the peripheral vein, the MRT of the DHAQ-CMS-MS group was 1.95 times that of the solution group. This means that the drug when loaded in microsphere will be concentrated in its targeted site for a longer period, which is favorable for the treatment of hepatic cancer.