Abstract: In order to improve the surface properties of carbon fibers and the interface properties of carbon fiber/resin composites, high modulus carbon fibers (HMCF) were treated with the polymer coating. The influence of the content of latent curing agent (LCA) in the coating layer on the carbon fiber surface properties and interface properties of carbon fiber/resin composites were studied. The results show that the polymer coating may have chemical reaction with carbon fiber or resin by IR analysis. SEM and DMTA also show polymer coating can improve the interfacical properties of carbon fiber/resin composites. The amount of LCA in the coating layer is the crucial factor to improve interfacial properties of carbon fiber/resin composites. When the content of the LCA is 20%, the interlaminar shear strength (ILSS) of the sized HMCF/epoxy resin composites is improved to 77.9 MPa, increased by 8.6% compared with that of the composites reinforced by unsized HMCF.