Ultrasonic cavitation treatment of polymer bonded explosive (JB-1) was undertaken. Before and after treatment,the surface structure of JB-1 explosive was observed by scanning electron microscope (SEM),and its element concentration was analyzed by X-ray energy spectrum (EDS). The results show that the interface between explosive crystal and binder is debonding during the ultrasonic treatment,and explosive crystals appear on the surface. With the treatment time increasing, the exposed extent of explosive crystal and the number of micro-hole on the surface of explosive crystal increase. As the surface of JB-1 explosive become rough and loose after ultrasonic cavitation treatment,its initiation sensitivity may also increase.