Y2Hf2O7 coating was prepared by SAPS on the surface of SiC coated C/C composites with distinct spraying power. The effect of spraying power on the microstructure, phase composition and bonding force was investigated. Meanwhile, thermal shock test has been conducted to evaluate the performance of the coating in extreme environments. Results show that Y2Hf2O7 coating prepared under 50 kW possesses optimal microstructure and combination state. The bonding force of the interface between Y2Hf2O7 and the SiC coating reaches up to 27.2 N. Compared with single SiC coating, composite coating shows a better protection of C/C composites from oxidation under thermal shock test. In addition, the coatings show excellent phase stability both in preparation and thermal cycles. Therefore, SAPS is an excellent method to prepare Y2Hf2O7 coating and the coating can be used as a potential environmental barrier candidate for C/C composites.