Abstract: Through observing the change of morphology and contact angle of coal ash column on the surface of refractories with increasing temperature, surface wettability of refractories was determined. The erosion and permeation behavior of coal ash on refractories during coal ash sintering process were observed and analyzed by using scanning electron microscope (SEM) and energy spectrum analysis. The morphology of slag sample, cross-section image of refractories and the change of element were studied. The results show that temperature is an important factor which influences the wettability and erodibility of coal ash on the surface of refractories. The erosion-resistance to coal ash varies between different refractory, which depends mainly on the composition and structure of refractories. Among these factors, compact structure is especially important. In fact, the corrosion of coal ash on refractories is the result of corrosion and permeation mineral elements between coal ash and refractory materials. During the process of corrosion, chemical reaction inhibits or promotes the corrosion. The wettability of coal ash on the surface of refractories is accordant with erosion behavior of coal ash on refractories.