The single crystal of 2,4-dinitroresorcinol was prepared and characterized by elemental analysis,IR and DSC. Its crystal structure was determined by a four-circle X-ray diffractometer. The results show that the crystal is of orthorhombic system. Space group is P2₁2₁2₁ with crystal parameters of a=0.4761(1)nm，b＝0.6378(1)nm，c=2.3990(2)nm，V＝0.7285(4)nm³，Z＝4，D_C＝1.825g·cm^-3，μ＝0.168mm^-1，F(000)＝408.