［Objective］To enhance the applicability of polytetrafluoroethylene（PTFE）composite coatings in the severe working conditions of wind turbine plain bearings.［Methods］ A polytetrafluoroethylene（PTFE）-based composite coating was developed by incorporating modified boron carbide（B₄C）and hexagonal boron nitride（h-BN）. The coating was prepared on a tin-bronze substrate using a spray-thermal curing process，and the effects of filler content on its tribological performance were investigated.［Results］B₄C was surface-modified with the silane coupling agentKH550 to enhance its dispersion and compatibility with the matrix. Meanwhile，h-BN，acting as a solid lubricant，formed a stable lubricating transfer film at the frictional interface due to its layered structure. The synergistic interaction between the two fillers enhanced the wettability，thermal stability，and mechanical properties of the composite coating. Experimental results showed that the composite coatingcontaining 4% h-BN and 6% modified B₄C exhibited the best tribological performance，achieving a35% reduction in the coefficient of friction and approximately a 50% decrease in wear rate. Analysis via3D profilometry，ultra-depth optical microscopy，and scanning electron microscopy（SEM）revealed that the addition of B₄C and h-BN effectively reduced crack density and abrasive particle accumulationon the worn surface. Furthermore，the high hardness of the modified B4C particles enhanced the load-bearing capacity of the coating，while the lubricating effect of h-BN significantly mitigated adhesiveand abrasive wear. The dominant wear mechanisms observed in the composite coating were abrasivewear and adhesive wear.［Conclusion］ This work proposes a friction-reducing and wear-resistantmechanism based on multi-particle reinforcement and lubricating film protection，providing theoreticalsupport and technical reference for the extended application of PTFE-based composite coatings in windturbine sliding bearings.