Abstract: Copper microparticles were synthesized with solution phase reduction from a mixture of Cu2+ ions and poly(ethylene imine)(PEI). The prepared microparticles were observed by scanning electron microscope. Rresults showed that the particles, which were obtained by chemical reduction of low concentration complexes of Cu2+ and poly(ethylene imine), presented regular morphology and uniform distribution, and the average particle diameter was about 0.98 μm. FT-IR spectroscopy and X-ray diffraction measurements revealed that the PEI bonded to metallic Cu microparticles to form a coating layer, no other oxidation state of metal Cu were found. Mass fraction of the coated PEI in the particles was 14.6%. Furthermore, the solution system of the copper microparticles formed in the presence of PEI possessed a good stability.