Composite material has attracted increasingly remarked interest over the last few decades and set it apart in its own class due to its distinct properties. World annual production is over 10 million tonnes and the market has in recent years been growing at 5-10% per annum. Among these materials, one subgroup, conductive polymer composite, has figured out and its importance is increasing in years to come. When used as conductive material, it possesses the merits of light weight, ease of manufacturing and chemical resistance. This review focuses on the electrical properties of carbon based conductive polymer composites. Special emphases are placed on the percolation phenomenon, the factors that affect the percolation threshold as well as related theoretical research work. Then mechanisms of electric conduction and factors influencing conductive properties are addressed.