Interfacial adhesion is an important parameter in carbon fabric-reinforced polymer composites. Due to the incompatible surface of fabrics; weak adhesion and poor interfacial bonding with polymer layer is observed. Surface treatment is a common method to overcome weak interaction between the components of the composites. The aim of this study is to improve the interfacial adhesion between the layers of polystyrene (PS)-based carbon fabric (CF)-reinforced composites. Polymer composite containing PS, elastomer (E) and carbon nanotubes modified with silane coupling agent (S-CNT), and modified CFs were used as the layers of the multiscale composites. These composites were characterized in terms of their structure (FTIR analysis), adhesion strength (T-peel Test), work of adhesion (Contact Angle Measurements) and morphology (Optical Microscope Imaging). The modification techniques which were applied to the layers were silane coupling agent (SCA) treatment, in-situ polymerized PS-E coating, electrospinning of polyamide 6 (PA6) on CF surface and combination of these methods. PS-E-S-CNT composite was prepared by using a co-rotating twin screw extruder. PS-E-S-CNT layers and the multiscale composites were prepared by using compression molding method. FTIR spectra of the peeled surfaces showed the characteristic peaks belonging to the different modifications. An increase was observed in peel strength with SCA treatment compared to the composite with unmodified CF. Peel strengths were lower when in-situ polymerized PS-E and electrospun layer of PA6 were directly coated on unmodified CF due to the lack of chemical interaction. The effect of SCA treatment on improving adhesion between the layers was clearly observed with the combination of these methods. Higher work of adhesion values were obtained in the composites showing higher peel strength. The samples with better adhesion exhibited rough surfaces which were observed with reflecting mode in optical microscope.