Abstract: In order to explore the adhesion and deposition characteristics of Shenmu fly ash (FSM) from ash-agglomera- ting fluidized-bed gasifier,on the basis of analyzing the particle size of FSM samples,the ash fusion temperature (AFT) and chemical composition of each particle size range of FSM and Shenmu coal were determined by ash fusion tempera- ture analyzer and X-ray fluorescence spectrometer ( XRF). The results show that particle size distribution of FSM is wide and has multi-peak. With the decrease of FSM particle size,the Ca,Fe,Si content of FSM are higher than that of coal,Al content is lower than that in raw coal,which results in the AFT of FSM is lower than that of raw coal. FSM with particle sizes in the range of 0. 15-0. 25 mm may behave a greater effect on adhesion because of their silicate glassy material formation and the calcium or ferrite low melting point eutectic. Based on the analysis on the formation process and the stress of FSM particles,the process of adhesion and deposition on the wall was discussed,and its model was also established.