Micron and submicron SiC powders were used as matrix for preparation of new type direct bond SiC refractories.The effects of different particle size distribution on the bulk density apparent porosity and linear shrinkage of pressureless sintered samples at 2 100 ℃ were investigated.The experimental results show that after sintering at 2100 ℃,the linear shrinkage increases with the increase of SiC  powder.When the matrix is pure submicron SiC powder,the sintering activity of the sample is better than that of the sample with micron SiC powder and the sample with micron-submicron mixed SiC powder.