The combustion behaviors of liquid energetic materials, HY91 and OTTO-II, were investigated by using their droplets in the high temperature range of 700～850℃. The ignition delay, lifetime, ignition temperature and average mass burning rate of the droplets were measured by a high-speed camera and two thermocouples. The results show that OTTO-II is ignited earlier than HY91, but its burning rate is much slower than the later. These data obtained are of practical references for improving the igniter and injection device of the regenerative liquid propellant gun（RLPG）.