Abstract: Studies were made of the material of Bop ZG25CrNiMo crack specimens tension damage and rupture behavior by using acoustic emission technique. The AE instrument recorded the ZG25CrNiMo crack specimens AE signal during tension process, and the AE data of the crack specimens of ZG25CrNiMo were analyzed by AE parameter and waveform analysis method. The type of damage and different stage characteristics during tension process were thus obtained. The result showed that rupture mechanism had significant effect on the AE signal feature during tension process, and that there existed big differences in the signal spectrum characteristics in different damage stages.