A novel method for preparing conductive carbon black fllled polymer composites with low percolation threshold from polyurethane emulsion are reported in this paper. The experimental results indicate that with a rise in carbon black concentration the insulator-conductor transition in the emulsion blended composites occurs at 0.8-1.4vol%. In contrast, the solution blended composites exhibit drastic increase in conductivity at conducting filler fraction as high as 12.3-13.3vol%. It is demonstrated that the composites microstructure rather than chemical structure of the matrix polymer predominantly determines the electrical conduction performance of the composites. A novel method for preparing conductive carbon black fllled polymer composites with low percolation threshold from polyurethane emulsion are reported in this paper. The experimental results that with a rise in carbon black concentration the insulator-conductor transition in the emulsion blended composites occur at 0.8- 1.4 vol%. In contrast, the solution blended composites exhibit drastic increase in conductivity at a conducting filler fraction as high as 12.3-13.3 vol%. It is characterized that the composites microstructure rather than chemical structure of the matrix polymer predominantly determines the electrical conduction performance of the composites.