High-performance yttrium oxide-phenolic resin (Y₂O₃-PF) alternating coating was prepared on epoxy resin-based composite material using supersonic plasma spraying and dual-channel powder feeding technique. Y₂O₃-coated PF (Y₂O₃/PF) powder was firstly sprayed onto the substrate, forming a transition layer, and then the spherical Y₂O₃ powder and Y₂O₃/PF powder were alternately deposited to form the composite alternating coating. Results show that the alternating coating is mainly composed of deposited Y₂O₃/PF powder. The bonding strength between coating and substrate is as high as 26.48 MPa with the single-test maximum bonding strength of 28.10 MPa, and shear strength reaches 24.30 MPa. Additionally, the heat transfer effect caused by external Y₂O₃ particles gradually softens and even melts PF, thus effectively avoiding the damage of high temperature to molecular structure and thereby promoting the crosslinking and curing effects of resin during the deposition process. In the meantime, the unmelted Y₂O₃ powder results in the shot peening effect, which washes out and eliminates the powder particles with inferior deposition effect, ultimately improving the physical and chemical properties of the alternating coating.