The experiments of Zhundong coal and its blended coal in 20%O2/80%N2 atmosphere in this paper were carried out in a drop tube fllrnace （DTF）. A temperature-controlled ash deposition probe was inserted from te bottom of the furnace to sainple. Total ash aild deposits were charac- terized by XRF, XRD and SEM-EDS. The total ash of the blended coal contained more refl＇actory quartz and mullite and less fluxing nfinerals like CaO and CaSO4. It increased the ash fusion poim and alleviated deposition tendency of Zhundong coal. Deposits of Zhundong coal sampled in 900℃ could be divided into an inner layer and an outter layer. The enrichment of Na2SOI and CaSOI was observed in the inner layer. The inner layer was mainly composed of smaller particles of 1-10） [tin, the outer layer was mainly composed of larger particles of 20-50 μm. The similar phenomenoll wasn＇t observed in 1150℃ and Deposits were mainly composed of Ca, Mg and S. In 900℃, deposition tendency of Zhundong coal was more serious.