<p>The propagation of rock-ice avalanches often involves the issue of ice melting. Laboratory flume tests were performed to investigate the influence of ice particle melting on the dynamics of rock-ice avalanches. The heat source for ice particle melting was provided by preheating the rock particles. Two ice particle sizes and six rock particle preheating temperatures (0–50 ℃) were set as variable conditions. The apparent friction coefficient, basal normal stress, pore water pressure, and meltwater form were analyzed. First, our findings indicate that fine-grained ice-mixed granular flows tend to produce more meltwater than coarse-grain ice-mixed flows under equal conditions. We suggest that sufficient contact of fine-grained ice with rock particles provides a favorable space for heat exchange and accelerates the melting. The results of the 12 sets of tests indicate that the influence of ice particle melting on the dynamics of mixed granular flow depends on the meltwater volume. When there is less ice melting inside the granular flow, meltwater exists mainly in the form of granular surface water and intergranular bonding water, which exhibit inhibitory effects on the mobility of the granular flow. Our observation supports that the suction force provided by the bonding water increases the cohesion of the granular flow system. When the amount of meltwater grows (preheating temperatures &gt; 20 ℃), the basal pore water pressure increases, reducing the shear resistance at the base of the flow. Finally, we suggest that the lubrication effect provided by the basal flowing water convergence layer, with the melting-induced rounding effect of the ice particles, also enhances the mobility of the rock-ice mixed granular flow. These findings contribute to the dynamic behavior assessment of rock-ice avalanches involving ice-melting issues.</p>