Communication: A new method to synthesize uniform polyaniline-coated composite microparticles was contrived considering the surface reactivity and porous structure of substrate polymer particles. It was found that the pore diameter together with the epoxy functional group plays a crucial role in controlling the structure of polyaniline shell. The polyaniline composite particles produced om this study are believed to find great applicability in piezoelectronics and as electro-rheological fluids.