Nanocopper (nano-Cu)/poly(acetoacetoxyethyl methacrylate (AAEM)-styrene (St)) (P(AAEM-St)) composites were synthesized by reducing copper acetate solution in AAEM and St monomer by ultrasonic technique without adding emulsifier. The morphology, structure, thermal stability, and the interaction between Cu nanoparticles (NPs) and P(AAEM-St) matrix of the composites were characterized using ultraviolet-visible spectroscopy, X-ray diffractometer, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), respectively. The results show that Cu NPs possessed face-centered cubic structure, and they were homogeneously dispersed in P(AAEM-St) matrix. XPS and FTIR analyses reveal the interaction between Cu NPs and C¼O of the acetoacetoxy in the copolymer of AAEM and St. TGA proves that the thermal stability of the pure P(AAEM-St) is higher than that of the nano-Cu/P(AAEM-St) composites.