Silicon carbide fiber-reinforced silicon carbide ceramic matrix composites (SiC_f/SiC CMCs) are considered strategic thermal, structural materials for advanced aircraft engines due to their lightweight, high specific strength, and excellent high-temperature capability. In harsh combustion environments, environmental barrier coatings (EBCs) are required to protect SiC_f/SiC CMC from water vapor corrosion and low-melting-point oxide corrosion, ensuring the long-term serviceability of SiC_f/SiC components. The development of next-generation high thrust-to-weight ratio aero engines has imposed more stringent requirements on the service life and temperature resistance of EBCs. Typical EBCs consist of a ceramic topcoat and a Si bond coat. However, the water vapor corrosion and oxidation of Si are essential factors contributing to EBC failure during service. Doping rare earth elements into the Si bond coat is expected to enhance its high-temperature capability and corrosion resistance, making it a promising strategy for developing advanced bond coat materials. For rare earth element-modified Si bond coat materials, composition variations fundamentally influence performance changes, including phase composition. However, the composition-property relationship of rare earth-modified Si bond coats remains unclear. In this study, Yb–Gd modified Si bond coat material chips were prepared using multi-target magnetron sputtering for co-deposition and were characterized using a high-throughput method. Transformation trends were identified by analyzing the phase composition and micromorphological changes in different Yb–Gd silicide compositions under extreme conditions (1100 and 1300 °C in an air atmosphere and 1300 °C in a water vapor-air atmosphere). It was found that the primary oxidation products of the Yb–Gd–Si ternary rare earth (RE) silicide at high temperatures are RE_9.33(SiO₄)₆O₂ and RE₂SiO₅ (where RE = Gd, Yb). RE₂SiO₅ undergoes a phase transformation from X1 to X2 as oxidation temperature increases. The morphology of Yb–Gd–Si silicide varies with composition after high-temperature water vapor corrosion. The corrosion mechanism involves initial oxidation, followed by the dissipation of Si and RE in the form of Si(OH)₄ and RE(OH)₃ under water vapor flow, where different silicon contents lead to distinct corrosion morphologies. A high-throughput performance database for RE silicide was established, enabling the regulation of component combinations to influence the phase composition of the bond coat material. This approach facilitates the development of new bond coat material with high melting points for extreme conditions.