In order to obtain detailed understanding of coal ash sintering behavior, a series of experiments have been done on the effect of Jincheng coal ash composition on sintering temperature under gasification atmosphere by the pressure-drop technique. The mineral transformations within its sintering temperature range are simulated by the thermodynamic equilibrium calculation module of FactSage to better understand the experiment results. These results show that the sintering temperature decreases initially, and then rises with increasing SiO2. On the whole, the sintering temperatures decrease with increase in Fe2O3, CaO, Na2O, and K2O. Their effects are quite similar, but the degrees are different. As MgO increases, the sintering temperature decreases. However when MgO is increased above a certain limit, the effect of MgO on the sintering temperature is not obvious.