Abstract: Submicron particle morphology spherical precipitation RDX was successfully prepared by supercritical rapid expansion (RESS) with liquid dimethyl ether (DME) as solvent. The effects of extraction temperature, extraction pressure and nozzle inner diameter on the RESS process were discussed. The process was optimized based on the Box-Behnken response surface methodology and the product performance was characterized in the end. Results show that the influence of all three factors is significant, and the inner diameter of the nozzle has the greatest influence, followed by the extraction pressure. The optimization parameters are extraction temperature 293 K, extraction pressure 15 MPa, and nozzle inner diameter 50 μm. RDX products show particle and spherical morphology, with sub-micron size and average particle size of 0.183 μm. The crystal enthalpy change (ΔH=714.4 J/g) is higher than that of the original RDX (ΔH=381.5 J/g), and the estimated explosion probability decreases from 76% to 55%. On the whole, the explosion performance of the newly prepared RDX is obviously improved, the violence increases and the sensitivity decreases.