Abstract: Granular coke reinforced pitch-based carbon composites (CRPCC) with high density and low cost were fabricated by a new mould pressing and semi-carbonization technology. The effect of the average particle size of the granular pitch coke on the density and compressive strength of CRPCC materials was studied in detail. The rules about the effect of the density on the compressive strength of CRPCC materials were mathematically analyzed. Results show that the density and the compressive strength increase with an increase of the average particle size of granular pitch coke. In the experiment, the density and compressive strength increase from 1.28g/cm3 to 1.77g/cm3 and from 10.1MPa to 55.0MPa respectively when the average particle size of the granular pitch coke as reinforcement rises from 44.2 to 206.3mesh.