Abstract: In order to explore the deformation features and dynamic constitutive relation of outburst coal under impact load, the impact compression test under different strain rate of outburst coal from B₆ coal seam in Huainan Coal Mine was carried out by split Hopkinson pressure bar (SHPB) of 75 mm in diameter. Combined with the existing constitutive model of rock material, a new dynamic constitutive equation for outburst coal has been proposed. The test result shows that the whole deformation process of outburst coal under impact load includes four stages basically: the initial nonlinear stage, yield stage, strain-hardening stage and unloading damage stage; and the fitted dynamic constitutive equation including damage effect and strain rate effect can fit dynamic stress-strain relationship of outburst coal before peak stress.