The crystallization refinement of RDX was performed by the process solution enhanced dispersion technique of supercritical fluids(SEDS) method. Exploring experiments were conducted to determine the DMF as solvent and the concentration of RDX/DMF solution as 20%.The factors affecting the refinement efficiency of RDX were investigated and analyzed via orthogonal L₉(3⁴)test design and single factor experiment. The results show that suitable solvent is the key to avoid obtaining flake or needle-like crystals. The order of factors affecting the effect of crystallization are pressure, CO₂ flow rate, sollution flow rate and temperature. As the fluid density is close to liquid density, the ratio of CO₂ flow rate and solution flow rate is directly related with granular proportion and the particle size, but the concentration determines the particle size ultimately. The expanding process conditions are concentration 26.7%, temperature 35 ℃, pressure 9.0 MPa, solution flow rate 2 mL·min^-1 and CO₂ flow rate 6 kg·h^-1. Under these conditions the edge of fine RDX particles obtained is smooth, and shape nearly spherical. The particle size distribution is uniform between 3~5 μm, and the fine RDX particles have good fluidity and low mechanical sensitivity. Its preparation amount can be up to 32 g·h^-1.