The bidirectional segregation competition and synergy between particle size, density, and friction differences in rock-ice avalanches have been insufficiently studied. This research combines physical flume experiments with discrete element simulations to systematically investigate the segregation evolution process and the competitionsynergy mechanisms among these physical properties. The results indicate that particle size differences are the primary factor controlling the segregation pattern, followed by density differences, with friction differences having the least impact. As the particle size ratio exceeds 1, the segregation mode shifts from ice particles moving upward and forward to rock particles moving upward and forward. The interactions between these properties generate either competitive or synergistic effects, depending on the direction and dominance of the driving factors. These findings provide key insights into the dynamics of rock-ice avalanches and contribute to improving hazard assessment and mitigation strategies.