Abstract: Monte Carlo simulation for breakage process during grinding was studied. The error of Monte Carlo simulation was in reverse proportional to the number of particles in the computation box， which caused the conflicting between the computation accuracy and cost. The main target of this work was to accelerate simulation while keeping its accuracy. First， main steps of the eventdriven Monte Carlo simulation were listed. Then， an improved sampling method was proposed to tackle the problem of the poor performance of traditional rejection sampling. Simulation experiments of batch grinding were designed. The results showed that the proposed algorithm could obviously reduce invalid sampling， and increase the simulation speed up to 5 times while keeping good simulation accuracy.

Key words: grinding process, breakage process, Monte Carlo simulation, rejection sampling, simulation speedup