The commonly used precursor to manufacture carbon fibers is rayon. The lower modulus material has a fiber electrical conductivity of 40,000 S/m and high modulus is 190,000 S/m [25]. Normally, the matrix material is nonconductor. Therefore, carbon fiber based materials show a low electrical conductivity. In CFRP inspection using eddy current pulsed thermography, the induced eddy currents in the carbon fibers can heat the fibers directly. While, there is no induced EC heating in the polymer matrix and their heat is from surrounding carbon fibers. Therefore, the carbon fiber will show the higher temperature than polymer matrix in the heat phase under both reflection transmission modes.