Using coal tar pitch as a matrix precursor to prepare carbon materials is widely used by impregnation/carbonization processing technology. Four different grades of coal tar pitch and a natural pitch were characterized in terms of carbon yield, density, viscosity,and fractionation with solvents, as well as by thermal analysis methods. The suitability of these commercially available matrices for densification of 3 dimensional carbon-carbon composites was examined. The theoretical results compared with experimental results.The highest density after impregnation was obtained using one of the coal tar pitches. The predicted results are in reasonable agreement with experiment data. The significance of this research is that a special heat treatment regime was conducted. The effects of modification temperature on the densification efficiency of composites were investigated and then structure and characteristics of the composites were determined by scanning electron microscopy (SEM), Transmission electron microscopy(TEM) and X-Ray Diffraction (XRD).