In this work, a black vacuum-plasma-sprayed Ta2O5 coating (VTO) was fabricated using white Ta2O5 powder as a raw material. Interestingly, a gray Ta2O5 coating was obtained by heat treatment of VTO coating (HVTO). The morphology, phase composition, photothermal conversion and cancer therapy effect in vitro of VTO and HVTO were comprehensively evaluated. Experimental results showed that VTO exhibited higher photothermal conversion effect and had an efficiency of 30.8% with high photostability. It has been proved that the VTO coating could be used in potential applications for bone tumor therapy.