In order to realize the high-value recycling of waste textiles, waste cotton fabrics were recycled, coated and finished, and cotton fabric-reinforced polyphenylene sulfide composites were prepared by hot press molding technology. Tridecafluorooctyltriethoxysilane and silicone-modified aqueous polyurethane were used to finish the cotton fabrics, and the performance of the latter-finished cotton fabric-reinforced polyphenylene sulfide composites was found to be better by tensile strength comparison. Silicone-modified waterborne polyurethane-modified cotton fabric-reinforced polyphenylene sulfide composites with different hot pressing temperatures and different concentrations were prepared. The effect of silicone modified waterborne polyurethane-treated cotton fabrics and their composites was evaluated using FTIR, super depth-of-field video microscopy and scanning electron microscopy, and the mechanical properties, surface wettability, thermal stability and thermal conductivity of the prepared composites were evaluated. The results showed that the silicone modified waterborne polyurethane finishing improved the interfacial adhesion of the composites. The prepared composite has 167% higher tensile strength, 160% higher flexural strength and 66.8% higher impact toughness than the original polyphenylene sulfide. The prepared composite has good thermal stability and thermal conductivity, which is suitable for medium load applications, including automobile body parts and structural components that require sufficient strength.