Abstract: With the synthesized spinel and mullite, MgO, Al2O3 and SiO2 powders as raw materials, the cordierites were synthesized by solid state reaction at 900-1 350 ℃ for 3 h with different raw material composition. The effects of raw material composition on the phase composition, density and microstructure of the synthesized cordierites were studied. The results show that the cordierites were all produced at 1 250 ℃, showing little influence of the raw material composition on the formation temperature. Meanwhile the spinel phase appeared invariably during the phase evolution process at 1 250 ℃ and above. The cordierites prepared using spinel or mullite as raw materials had a higher density than that with pure oxides as raw materials, moreover the grain growth was more complete and the grain size was larger.