Abstract: The ash deposition from the combustion of Zhundong coal can be alleviated with the addition of kaolin, while the cost of the method is high. Taking the Zhundong coal ash with different particle sizes as the additives, combined with the ash deposition experiment in a drop tube furnace and the sintering experiment in a fixed bed furnace, an evaluation was conducted on the control effect of ash deposition of Zhundong coal ash with different particle sizes. Results show that the composition and the mineral distribution of Zhundong coal ash with different particle sizes are distinct, and the content of silicon-aluminum minerals such as mullite in coal ash of more than 100 μm is significantly higher than that in the coal ash of other sizes. The ash depositon on the heat exchange surface is easily to be removed with the the addition of coal ash of more than 100 μm, however, the coal ash of less than 50 μm not only could not prevent the development of deposition, but also could aggravate the removal difficulty of the deposited ash. The less removal difficulty of the deposited ash on the heat exchange surface is mainly caused by the weaker sintering with the addition of coal ash of more than 100 μm.