Flexible dielectric materials composed of polymer matrix and ceramic fillers with high dielectric constant have attracted more and more attention in microcelectronic device field. In this work, conductive polyaniline (PANI) organics were in-situ synthesized and coated on the surface of CCTO particles, and then the mulberry-like CCTO@PANI particles were incorporated into natural rubber (NR) to prepare the polymer composites. Coulomb-blockade effect is observed when the conductive clusters PANI is embedded in an insulating matrix. Compared with CCTO/NR composites, although the dielectric constant of CCTO@PANI/NR composites decreased slightly, but it still maintained excellent breakdown strength. The method provides a promising way to coordinate and prepares dielectric composites with dielectric properties. [ABSTRACT FROM AUTHOR]