Abstract: The effect of ashing temperature on the apparent morphology of poplar ash was investigated by muffle furnace burning experiment. The physicochemical properties of poplar ash prepared at different ashing temperatures(600, 800, 1 000 ℃) were compared and analyzed by X-ray diffraction, scanning electron microscopy and energy spectrum analysis. The melting characteristic temperature of poplar ash was measured by ash melting point tester. The relationship between melting characteristic temperature of poplar ash and ashing temperature and residence time was revealed. The poplar ash with ashing temperature of 800 ℃ and residence time of 2 h was treated to the deformation temperature(DT) state. The physicochemical properties of poplar ash during the melting process were analyzed, and the melting performance of poplar ash was further studied. The results showed that the main mineral crystal phases of poplar ash were K₂SO₄, KCl, SiO₂, K₂Ca₂(SO₄)₃, Na₂Si₂O₅ and so on when the ashing temperature was 600 ℃ and the residence time was 2 h. Under the conditions of the ash formation temperature of 800 ℃ and the residence time of 2 h, the main mineral crystal phases of poplar ash were MgSiO₃, Na₂Si₂O₅, Na₆Mg(SO₄)₄, SiO₂, CaSO₃ and so on. The XRD pattern of poplar ash at 1 000 ℃ was similar to that at 800 ℃. At 600 ℃, the poplar ash had obvious holes and the surface structure was relatively complete. With the increase of temperature, the surface structure of poplar ash had obvious damage, and the holes in the surface structure gradually increased. The melting characteristic temperature of poplar ash had a positive correlation with the ashing temperature, while there was no obvious linear relationship with the residence time. The deformation temperature(DT), softening temperature(ST), hemisphere temperature(HT) and flow temperature(FT) of poplar ash obtained at 800 ℃ for 2 h were 1 224, 1 254, 1 267 and 1 294 ℃, respectively. When the poplar ash was treated to DT state, the floccule disappeared, and there were still a few holes on the surface, with small particles of ash embedded in the holes.