A high-quality conductive polypyrrole was prepared within a secondary crosslinked interpenetrating polymer network by chemical oxidative polymerization, whose conductivity is high up to 0.25 S/cm only with 0.9% polypyrrole. The "microfiber" structure of polypyrrole was characterized by scanning electron microscopy, polarizing microscopy, and small angle X-ray diffraction. The formation of the microfiber was strongly dependent on the structure of the matrix. This might provide a new method for the preparation of conductive microfibers.