According to the situation that most power plants fueled mainly with ravens, the Lengshui river coal ash was elected as base-ash simple, prepared ash-simple with MgO concentration of 4 %, 8 %, 12 %, 16 % respectively, and then placed them into SDAF2000b ashmelting-point instrument successively to measure the DT,ST, HT,FT. Put the ash-simple uniformly and loosely on SiC corundum and high-aluminum based refractory boards and then sintered them in a muffle for 20 h under 1 250 ℃. XRD analyses showed that ash fusion point decreased with the content of MgO increased, and the lowest point appeared in the content of 5%. However, the strength of slagging enhanced, while MgO still increased, the ash fusion point rose. SiC refractory and Aluminum base refractory have the same slagging adaptability with the same content of MgO.