Abstract: Through dynamic compression testing of ER8 steel, the microstructure evolution behavior under high-speed impact as well as the yield, deformation, and fracture behavior of specimens were analyzed, thereby providing theoretical guidance for its service safety. The conclusions are as follows: With increasing engineering strain rate, both the yield strength and peak stress of ER8 steel show an increasing trend. The yield strength exhibits relatively large fluctuations in its growth trend, while the peak stress fits well with the Asymptotic1-type growth law, which can be described as: the peak stress "increases first and then saturates" with increasing strain rate. Overall, at a strain rate of 5500 s⁻¹, the specimen achieved the highest yield strength and peak stress, reaching 961 MPa and 1068 MPa, respectively. For the ER8 steel studied within the strain rate range of 560 s⁻¹ to 5520 s⁻¹, none of the dynamically compressed specimens fractured, and ASB or shearing bands did not extensively form in the samples, demonstrating low adiabatic shear sensitivity.