Abstract: Conductive polymeric composites were prepared from Carbon Black(CB),Nitrile Butadiene Rubber(NBR) and a kind of organic crystal. The relationship between the resistivity of NBR/CB(N550) composite and temperature exhibits PTC (Positive Temperature Coefficient) phenomenon to some extent. Some influences of organic crystal on the resistivity of composites at room temperature and PTC effect of the composites were investigated in detail.