Environmental barrier coating (EBC) is essential for protection of ceramic matrix composite hot-sections in future gas turbine engines with high thrust-to-weight ratio. Rare-earth silicates, such as Yb 2 SiO 5 and Yb 2 Si 2 O 7 , have been developed for potential application as EBC. However, the corrosion behaviors and mechanisms of EBC in molten salt environment such as Na 2 SO 4 at high temperature are not clear. In this work, the Yb 2 SiO 5 /Yb 2 Si 2 O 7 /Si coating was prepared by vacuum plasma spraying (VPS). The molten salt (Na 2 SO 4 +25% NaCl, in mass) corrosion behaviors and mechanisms of the coating at 900 ℃ for 60-240 h were investigated. Results showed that the Yb 2 SiO 5 /Yb 2 Si 2 O 7 /Si coating exhibited dense structure with good bonding between the triple ceramic layers. The molten salt of Na 2 SO 4 +25% NaCl penetrated the Yb 2 SiO 5 top layer and enriched in the Yb 2 Si 2 O 7 interlayer, while the interfacial