The tensile strength of a single soil particle is usually measured indirectly by compressing the grain between flat platens until failure occurs,and is defined as the tensile stress at whole-particle fracture. The tensile strength appears to decrease monotonically with the diameter of particles,and is usually characterized by the Weibull statistics. For granular materials,it is impossible to measure constant tensile strength,unless the flaw effect is taken into account in the framework of fractal. The fractal dimension of flaw distribution equals to that of the fragmentation of granular materials. The Weibull statistics is modified using the fractal model of flaw distribution. Goodness-of-fit statistics shows that the modified model fits the experimental data much better than the conventional model. The modified model has only one parameter,the fractal dimension of fragmentation D,which can be determined using the mass-size distribution.