To study the effect of high temperature blast hole on the explosion power of water bath protected emulsion explosive, the enviroment temperature of protected emulsion explosive in high temperature blast hole were simulated by 100 ℃ water bath heating and the underwater explosion parameters were caculated and obtained through underwater explosion experiments. Results show that the detonation velocity, shock wave impulse, specific shock wave energy, specific bubble energy and total energy of emulsion explosive decrease with the increase of water bath heating time. In which, the specific bubble energy and total energy of emulsion explosive decrease in approximately linearly with the increase of water bath heating time, whereas, the effect of increase of water bath heating time on the proportion of specific bubble energy in total energy is smaller and the proportion remains at about 65%.