Abstract: Poly(sodium-4-styrenesulfonate)(PSS)-decorated carbon black was prepared by one step in situ ball milling method. The resulting carbon black exhibited a superb stability in aqueous medium according to the results of particle size analysis and centrifugal sedimentation. Natural rubber (NR) filled with this kind of hydrophilic carbon black by employing a latex compounding technique was prepared. The compo-site was characterized and tested by mechanics performance testing, Scanning Electron Microscope (SEM), bound rubber content and Dynamic Mechanical Analysis (DMA). Owing to the homogeneous distribution of carbon black in matrix and the increase of the interaction between carbon black and NR molecular chain, an improvement in physical and mechanical properties was observed in the composites in comparison with the vulcanizate fabricated by traditional dry compounding. Futhermore, the extent of filler network was weakened according to the result of strain dependence of storage modulus and loss modulus tested by DMA.