To achieve the resource utilization of biomass and develop high-performance corrosion-resistant coating materials, carbon nanoparticles(CNs)and onion-like carbon(OLCs)were successfully prepared using hydrothermal synthesis and high-temperature carbonization methods, respectively. The two particles were added to polyimide materials to develop high-performance corrosion-resistant coatings. The influence of these particles on the corrosion resistance of polyimide coatings was investigated using an electrochemical workstation. The results indicated that the addition of biomass carbon nanoparticles and onion-like carbon particles had different effects on the corrosion resistance of polyimide coatings. The composite coating modified with onion-like carbon particles(OLCs/PI)significantly enhanced the corrosion resistance of polyimide compared to the composite coating modified with carbon nanoparticles(CNs/PI). The anti-corrosion mechanism is attributed to the hydrophilic nature of carbon nanoparticles, which tend to dissolve in simulated seawater, thereby reducing the corrosion resistance of the composites. In contrast, onion-like carbon particles are hydrophobic and provide additional tortuous paths for the penetration of corrosive media or act as micro-containers to store corrosive media, thus improving the corrosion resistance. Consequently, the prepared composites remain stable during seawater immersion, thereby enhancing the corrosion resistance of polyimide materials