Abstract: By the fractal method, mathematical models for particle number variation, particle surface area profile and particle mass distribution were established to predict and control the particle-size distribution of coal grinding at any grinding time. The particle number variation can be used to describe the main range of particle diameter. The surface area profile can be used to predict the energy consumption in grinding process. The particle mass distribution could be used to calculate the specific stacking density of particles or the slurry concentration. These models were proved to be valid by comparison of the fractal particle-size distribution with practical measurement.