Abstract: The reserved coal pillar in cold area is susceptible to destabilization and damage due to low temperature and mining action. In order to investigate the influence of impact velocity and length-to-diameter (L/D) ratio on the dynamic mechanical properties of low-temperature coal, the dynamic parameters and crushing energy-consuming characteristics were investigated based on the impact-compression test of split Hopkinson pressure bar (SHPB). The study shows that the dynamic stress-strain curve can be divided into microfracture closure, stable development of micro fracture, unsteady development of microfracture and rapid unloading stages. Dynamic compressive strength, modulus of elasticity, destructive strain, peak strain have strain rate strengthening effect and size weakening effect, and the temperature effect is not obvious; the dissipated energy density increases linearly with the increase of strain rate, and decreases linearly with the increase of L/D ratio; the entropy of crushing information can quantitatively express the crushing degree of coal samples, which shows an overall trend of increasing-decreasing-increasing with the decrease of temperature (−40-0 ℃), with the inflection points of −10 ℃ and −30 ℃, and linearly positively correlates, power function negatively correlates, and exponentially positively correlates with the strain rate, L/D ratio, and dissipated energy density, respectively.