Abstract: The effects of Methacryl-POSS coating on the interfacial properties of carbon fiber/polyarylacetylene (CF/PAA) composites were studied by means of micro-debonding measurement，three-point bend test，scanning electron microscopy (SEM)，force modulation mode atomic force microscopy (AFM)，and dynamic mechanical thermal analysis (DMTA). Wilhelmy method was used to study the wettability of PAA resin on the carbon fiber surface before and after treatment. The degree of surface roughness and the wettability of carbon fiber surface are both increased after POSS coating treatment. Compared with untreated CF/PAA composite，the interfacial shear strength (IFSS) and interlaminar shear strength (ILSS) of POSS coating treated composites are increased by 36% and 50%，respectively；the glass transition temperature of the CF/PAA composites modified with POSS coating is increased by 12℃ and the loss tangent (tan δ) is decreased by 53%. The interfacial bonding of CF/PAA composites can be improved effectively by using POSS coating.