The ordinary RDX was recrystallized in dimethyl sulfoxide (DMSO) solvent with Twin-80 crystal modifier to improve its morphology and reduce its sensitivity. Optical microscopy and density-bottle were utilized to analyze RDX sample before and after recrystallization,the results show that apparent density of recrystallized RDX is increased by 0.007 g·cm^-3 and the recrystallized RDX has more regular and smooth crystal morphology. The recrystallized RDX and ordinary RDX were used respectively in the same cast PBX formula. The shock sensitivity of the two formula was compared by small scale gap test (SSGT) equipment,the results show that recrystallized RDX formula has 25% lower shock sensitivity than ordinary RDX formula.