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 Yb₂SiO₅ and Yb₂Si₂O₇, have been developed for potential application as EBC. However, the corrosion behaviors and mechanisms of EBC in molten salt environment such as Na₂SO₄ at high temperature are not clear. In this work, the Yb₂SiO₅/Yb₂Si₂O₇/Si coating was prepared by vacuum plasma spraying (VPS). The molten salt (Na₂SO₄+25% NaCl, in mass) corrosion behaviors and mechanisms of the coating at 900 ℃ for 60-240 h were investigated. Results showed that the Yb₂SiO₅/Yb₂Si₂O₇/Si coating exhibited dense structure with good bonding between the triple ceramic layers. The molten salt of Na₂SO₄+25% NaCl penetrated the Yb₂SiO₅ top layer and enriched in the Yb₂Si₂O₇ interlayer, while the interfacial bonding between the coating and substrate still remained good after corrosion for 240 h. The Yb₂SiO₅ phase in the top layer exhibited good stability, while the second phase of the Yb₂O₃ reacted with molten salt. The content of the Yb₂O₃ decreased with the increase of corrosion time. The Yb₂Si₂O₇ phase in the interlayer reacted with molten salt to form apatite phase of NaYb₉Si₆O₂₆ and sodium silicate as well as volatile species such as Cl₂ and SO₂, which might shorten the service life of the coating. Moreover, there was almost no molten salt in the silicon bond layer, which remained intact. The Yb₂SiO₅/Yb₂Si₂O₇/Si coating exhibited good resistance to molten salt corrosion.