The recrystallization process of RDX from concentrated nitric acid was studied to prepare the spherical RDX with particle size of 150-180 μm. The manufacturing process conditions are: RDX 35 kg,concentrated nitric acid (97) 135 kg,stirring rate 240 r·min^-1,the first diluent: dilute nitric acid (50%) dosage 80 kg,adding rate 8 kg·min^-1,temperature 45 ℃,heat preservation 10 min； the second diluent: water dosage 126 kg,adding rate14 kg·min-1,temperature 55 ℃. Results show that the content of particle size of RDX crystals from 150 μm to 180 μm are 69.3% by using the recrystallization process mentioned above.