A novel electro-activated Cu/pHEMA nanocomposite was fabricated by coupling nano copper particles with poly(2-hydroxyethyl methacrylate) (pHEMA) matrix. The nano-sized copper particles ranging from 5 nm to 10 nm were in-situ synthesized in the presence of three-dimensional polymer matrixes by photo-polymerization of the copper ions with the HEMA monomer and followed by a strong reducing reaction. The electrochemical behaviors of the Cu/pHEMA nanocomposite were charcterized by cyclic voltammetry and alternating current impedance method. The results showed that the redox behavior of Cu/pHEMA nanocomposite was controlled by the crystallinity of copper particles and the interaction between copper and pHEMA.