The ignition of aluminum particles under high pressure and temperature conditions is studied. The laser ablation method is used to generate aluminum particles exposed to pressures ranging between 0.35 and 2.2 GPa. A continuous wave CO₂ laser is then used to heat surface of the aluminum target until ignition is achieved. We confirm ignition by a spectroscopic analysis of AlO vibronic band of 484 ㎚ wavelength. The radiant temperature is measured with respect to various pressures for tracing of required heating energy for ignition. Then the ignition temperature is deduced from the radiant temperature using the thermal diffusion equation. The established ignition criteria for corresponding temperature and pressure can be used in the modeling of detonation behavior of heavily aluminized high explosives or solid propellants.