An unfired mullite roller was produced by using mullite roller waste, white fused alumina, α-Al2O3, clay and micro silica, meanwhile silica sol was used to partially substitute for micro silica as the SiO2 source. The effect of silica sol on the properties of unfired mullite roller was investigated. The results showed that the microstructure and properties of the unfired mullite roller prepared with silica sol were improved. With the increase of silica sol, the COMR, bulk density and thermal shock resistance increased, and the water absorption rate decreased. When silica sol was 8w/t%, treated temperature was 1200°C, the CMOR of unfired mullite roller was more than 50MPa.