The application of silica in the epoxidized natural rubber (ENR) without coupling agent was investigated. Severe aggregation of silica was found in the natural rubber (NR)， while in the ENR the aggregation was significantly reduced. In addition， the dispersion of silica could be improved by increase of the epoxidation degree. It was found that the silica filled ENR compounds exhibited good wet skid resistance and low rolling resistance. With more than 20 parts of silica， the silica/ENR compound had much lower dynamic heat build-up than carbon black filled NR.
