A new bioceramic coating based on diopside was prepared by plasma spraying. The surface and cross-section microstructure of the coating were examined by scanning electron microscopy. The thermal expansion coefficient of the diopside coating measured by a dilatometer adapted to that of titanium alloy. The bond strength of the coating was about 32.5 MPa, which is higher than that of HA coatings used in orthopedics and dentistry. The bioactivity of diopside coating was evaluated in vitro. After 15 days soaking in simulated body fluid, an apatite layer was formed on the surface of the coating. The cytocompatibility was investigated by studying the behaviour of human osteoblast cultured directly onto the surface of the coating. MTT assay was performed to assess the influence of the coating on cell proliferation. The morphologies of the cell were observed by SEM after incubation for 1 and 7 days. The results obtained indicated that plasma sprayed diopside coating may be a suitable candidate for bone and dental implant.