The destructive expansion of CFBC ash is the bottleneck problem for its utilization in building materials. The addition of chemical substances and autoclave curing were used to inhibit the expansion in the paper. The results show that the addition of 1% CaCl2 or 1% Na2CO3 can decrease the 28 d linear expansion ratio of CFBC ash-water mortars by about 19%, with no disadvantage influence on the compressive strength. Moreover, the linear expansion ratio of CFBC ash-clinker-water pastes was below 5×10-4 after autoclave curing. The work confirms that the expansion of CFBC ash can be inhibited effectively by the way of autoclave curing.