Objective To prepare protective coating for Ta-based alloy in the high-temperature oxidation environment . Methods Using slurry firing, the silicide composite coating was prepared on the surface of Ta-12W alloy. The bottom layer and the surface layer were prepared in proportion on the sample. Using two firing process, the silicide composite coating was prepared on the sample. The morphology, element content and composition distribution of the composite coating were investigated by SEM, EDS and XRD. The life of high-temperature oxidation-resistance at 1800℃ and the times of shock-testing from room temperature to 1800 ℃ of the coating were detected. The failure mechanism of the coating was discussed. Results The transitional layer between the coating and substrate is formed by diffusion, and the interface is metallurgical bond. The coating can be used at 1800 ℃ for 9 hours, and the limit time of shock-testing from room temperature to 1800 ℃ is 151 . Conclusion The glass layer on the surface of the coating, which is formed during the high-temperature oxidation environment, prevents oxygen from further diffusion and protects the material .