Objective To approach the sequential release of antitumor drugs and promote the effect of chemotherapy.Methods Adriamycin (ADM) and carboplatin (CBP) were respectively microcapsulated with ethylcellulose by organic phase separation. The morphology and sizes of the microcapsules were observed and measured with light microscope and scanning electromicroscope. The contents and the release rates of ADM and CBP in microcapsules were measured with fluorescence spectrophotometer and high-efficiency phantom chromatic (HPC) spectrum respectively. The antitumor sensitivity test in vitro was devised with MTT assay.Results The microcapsules of ADM and CBP were spherical in shape with diameters of 196?4 μm and 214?8 μm respectively. The contents of one-layer and two-layer CBP and ADM microcapsules were 51.4%, 35.7% and 39.8% respectively, with the release rates in vitro of 62.4%/day, 54.8%/day and 48.2% /8h. The results of drug sensitivity test in vitro demonstrated that the current preparation has never affected the stability and antitumor activity of CBP and ADM.Conclusion Microcapsules with different drugs and different thickness of material have different release rate. Combined arterial chemoembolization with different microcapsules could approach the sequential release and promote the effect of chemotherapy.