Conductive carbon-black (CB)-filled polyethylene composites were prepared after irradiation with a cobalt 60 source. The conductive composites were characterized by alternating-current impedance spectroscopy, and the conductive mechanism of the conductive composites was analyzed in terms of a mathematical model. The values of the conductive ability, conductive style, sum of the electrical resistance of the continuous CB chains, electrical resistivity of the CB chains with one gap or a few small gaps, room-temperature resistance, and slopes of the conductive composites were calculated. The investigation indicated that there existed continuous (contacting)-path CB chains, small-gap chains, and larger gap CB chains in the composites, and the conductive paths in the composites were considered to be a three-dimensional network. (C) 2008 Wiley Periodicals, Inc.