Objective：The chitosan microspheres encapsulated with bone morphogenetic protein-2 (BMP-2) were prepared by the emulsion cross-linking method. Then the chitosan microspheres were loaded in the ceramic bovine bone (CBB) to achieve the drug delivery system. Methods: The chemical structure and surface morphology of the drug delivery system were investigated by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) observation. Characterization preserved the loading capacity and encapsulation efficiency of the BMP-2. The dynamic immersion method was used to examine the in vitro release characteristic of BMP-2.  Results: The chitosan microspheres were successfully encapsulated BMP-2 by cross-linking method. The microspheres were micron-sized (5.982 μm) and spherical in shape with smooth surface morphology. From the release experiments, it was found that 5 mg chitosan/BMP-2 soaked for 21 days with a gradual release of BMP-2. The concentration of BMP-2 was (239.1±20.0) mg/L on Day 21. The in vitro experiment showed that this novel drug delivery system could accelerate MC3T3-E1 cells proliferation and osteogenic differentiation. Conclusion: The drug delivery system achieves the biological function of BMP-2 and sustaining slow release in bone repair parts. Also it can provide the basis for repair of bone tissue defect treatment and the selection of bone tissue engineering scaffolds.