In order to study the mechanical property of explosive crystals with different qualities,two recrystallized and a commercial grade RDX and HMX particles were selected and tested by compressive stiffness method. The Kawakita equation is applied in fitting the compressive curves. The fitting constant of the equation,which is of the reciprocal dimension of modulus,can be used to evaluate the mechanical property of energetic crystalline particles. For RDX,the fitting results are respectively 13.08,12.16 and 5.51,corresponding to the two recrystallized samples and the commercial grade one. And the values for HMX turn out to be 11.43,12.57 and 10.05 respectively. However,the results of the fragmentation stage in compression are reduced to 9.53,7.86,4.36 for RDX,and 6.13,6.48,5.56 for HMX. The study proves that the fitting constants can be used to evaluate the mechanical property of energetic crystalline particles,and it also shows that the results based on the fragmentation processes describe the real mechanical behaviors better.