This paper aims to reveal the effect of adding biomass ash on the flow characteristics of Zhundong (ZD) coal ash. A new visual image measurement method for the flowability of coal ash was established. Furthermore, scanning electron microscopy (SEM) and x-ray diffraction (XRD) were applied to analyze the influence of surface morphology and mineral component on the fusion fluidity of the samples. The results show that the flow properties of ZD ash are improved to varying degrees after adding maize straw (MS) ash. As the blending ratio increases, the improvement of flow velocity is higher. The critical flow temperature (T C ) of the samples was calculated. The T C of ZD ash was 1249 C, which decreased with the addition of MS ash. The characterization