In order to find the distribution law of coal fragmentation, mathematic model of size distribution was built according to fractal theory. Based on this, the experiments of impactive crash were carried out under different impact rate and different Protodikonov's hardness. The comparison between Weibull distribution and fractal distribution was done so as to find the relationship between the influence parameters and the coal fragmentation characteristic index, the coal fragmentation degree coefficient and the fractal dimension. The results indicate that both two types of distribution functions are suitable for the distribution discipline of coal fragmentation, but the relationship of the coal fragmentation degree and impact parameter is not reacted correctly by the coal fragmentation characteristic index and coal fragmentation degree coefficient in the Weibull distribution while the coal fragmentation degree could be expressed by the fractal dimension in fractal distribution. The relationships between the fractal dimension and the rate, the Protodikonov's hardness of coal are linear.