To explore theoretically the sensitivity criterion and the mechanical properties of PETN explosive crystal, molecular dynamics (MD) simulation periodic at 195, 245, 295, 345, 395 K for (4×3×4) super cells and its cutting model along (100) crystalline surface was conducted by COMPASS force field in the NPT ensemble. The results show that as the temperature increases, the maximum bond length (L_max) of their O—NO₂ trigger bond increases, the interaction energy (E_O-N) between O atom and N atom of the O—NO₂ trigger bond decreases and the cohesive energy density (CED) decreases. These results agree with the experimental fact that PETN becomes more sensitive as the temperature increases. The L_max、E_O-N and CED can be used as the theoretical criteria to predict the heat and impact sensitivity under certain conditions. With increasing the temperature, the elastic coefficients and elastic modulus decrease, the stiffness of PETN crystal decreases and the flexibility increases, which agrees with the experimental fact, indicating that the MD simulation of PETN cutting model is able to yield more concrete quantitative results.