When conducting blasting under deep water, the explosive will be affected by high water pressure and long-term water immersion conditions due to the long charging time. Only when the performance of the explosive meets the technical requirements can the blasting effect be guaranteed. Taking the waterway regulation project of Liantuo river between the Three Gorges Dam and Gezhouba Dam as the research background, it was found the original emulsion explosives composition was weak in resisting deep water pressure during the reef blasting. The detonation distance was small, and the intensity was insufficient during the construction at a depth of 40 m. The performance of water gel explosives, chemical-sensitized explosives, glass microsphere-sensitized explosives, and perlite-sensitized explosives were studied by experiments in the laboratory adjusted the hydrostatic surface pressure to simulate the deep-water condition by using the deep-water measurement method. A relationship between the explosive performance and immersion time was explored under different water depth conditions. Meanwhile, a relationship between the explosive performance and water depth was built under different immersion time conditions. Comparing the experimental results, the study shows that the performance of glass microsphere-sensitized explosives, chemical-sensitized explosives, perlite-sensitized explosives, and water gel explosives all slightly decrease and meet the engineering requirements when the water depth is 0~20 m. It is recommended to use glass microsphere-sensitized explosives and perlite-sensitized explosives when the water depth is 20~40 m, and the glass microsphere-sensitized explosives are suitable when the water depth is 40~50 m. Besides, the glass microsphere-sensitized explosives have relatively small performance degradation under high pressure and long-term immersion conditions, and it is suitable for underwater drilling and blasting construction in deep water conditions.