Abstract: The paper introduced the S-Kojovic model to simulate the relationship between the unit crushing energy of the mineral and the particle size reduced.The model was applied to the experiment study on the three impact crushing methods of three Australia coal samples, including the hammer drop crushing, rotary crushing a nd bed crushing.The study results showed that the S-Kojovic model could be well to simulate several impact crushing processes of coal and the related coefficient R2 a verage value could reach 0.975.In the bed crushing, coal crushing firstly should overcome a min unit crushing energy of 253.20 J/kg in average.In other two crushing m odes, the min unit crushing energy value could be neglected in calculation.In the impact crushing, the max particle reduced degree and crushing efficiency of the coal s ample would be related to the crushing method.The sequence from big to small of the two would be the rotary crushing, hammer drop crushing and the bed crushing.In addition, with the auliliary milling role influence of the high ash mineral, in the bed crushing, the hardness of the same coal would be reduced with the ash cantent incre ased.