Pentazoles are currently a research hotspot in the field of energetic materials， however， the stability of existing pentazoles is generally not high. In order to develop new pentazoles with better properties， based on the analyses of the available structures， 20 substituted derivatives of HN₅ with the electron-withdrawing groups， i.e.，N₅（CH₂）_x-1R（R=—NO₂，—CF₃，—CN， —CHO， —COOH； x=1， 2， 3， 4）， were designed and studied by using the density functional theory method. The bond dissociation energy （E_BD） of the bonds linked with the N₅ ring and the activation energy （E_a） of the cracking of the N₅ ring were calculated and compared with that of some pentazoles substituted by the electron-donating groups， and the effects of substituents on E_BD and E_a were discussed. Results show that the E_a of all molecules is much smaller than E_BD， indicating that the stability of the N₅ ring is the key factor to determine the stability of the pentazoles. When R is directly connected to the N₅ ring （N₅R）， the E_a of N₅R with R being an electron-withdrawing group is smaller than that of N₅R with R being an H or an electron-donating group. The N₅ ring is a strong electron-withdrawing group， and bearing too much or too little negative charges is not conducive to the stability of the N₅ ring.