The thermal behaviors of the smokeless NEPE propellants with and without CL-20 are studied by TG-DTG and PDSC. Experimental results show that there are two decomposition stages on the TG-DTG and PDSC curves of the propellants with and without CL-20 at normal and high pressure,and CL-20 decomposition at high pressure is in the first exothermic decomposition stage with the temperature range of 180-210 ℃. The total apparent decomposition heats of the propellants increase with the increase of the pressure and the content of CL-20,obviously.