Abstract: The dynamic distortional buckling of C-section cold-formed thin-walled steel under axial impacting was studied in this paper. The drop hammer impact testing device, high-speed camera and the digital speckle correlation method were used to carry out exploratory tests research and data analysis on the critical distortional buckling stresses and ultimate bearing capacities of C-section cold-formed thin-walled steel members under axial impact. The results of tests were compared with those of the numerical simulations from ABAQUS. It indicates that the critical stress of dynamic distortional buckling from simulation results are different with those from test results. The stress-strain curves of post-buckling from simulation and tests are in accord with each other. The ultimate bearing capacity of steel members under the axial impact was improved greatly.