In order to explore Zhundong ash deposition rules, the visualization of fly ash deposition test rig was used to study the deposition characteristics of Zhundong coal under different ashing temperatures. SEM-EDS, XRD and Particles Distribution Instrument were utilized to analyze ash particles. The results showed that the different ashing temperatures led to large differences in characteristics. Existence in the form of calcium is mainly CaCO₃, CaSO₄ at 500 ℃ and 650 ℃ cases, but CaO in the 800 ℃ case. At 800 ℃, NaCl is unable to be found in ash and Zhundong coal exists self-desulfurization. In terms of ash deposition characteristic, the 800 ℃ ash is the highest in fouling height because of larger diameter of particles. It is illustrated that the physical factors are the controlling factors at this experimental condition. The "uneven" phenomenon is also appeared at borders for 500 ℃ and 650 ℃ cases, because the particles form voids and are heated to become soft and easy to collapse. It is called "Boundary Roughening", which may be important reasons of fouling and slagging in boilers.