Abstract: In deep coal mine mining, high ground stress intensifies the deformation of surrounding rock in roadways. The columns of traditional roadway support with small extension ratio are prone to the “locking” phenomenon in the later stage of compression, which makes it difficult to withdraw the supports. To address this problem, an internal energy-absorbing column is proposed. By integrating the energy-absorbing device inside the cylinder block of the first-stage cylinder, the axial space occupation of the energy-absorbing guide section of the external energy-absorbing column is eliminated, thereby achieving an increase in the extension ratio and optimization of impact resistance performance. Based on the theory of elastic mechanics, an equivalent stiffness calculation model for both internal and external energy-absorbing columns is established, and the theoretical basis for the difference in their mechanical properties is clarified. The Smoothed Particle Hydrodynamics method is used to conduct fluid-solid coupling numerical simulations, and the response characteristics (such as support reaction force, liquid pressure, and cylinder stress) of the two types of columns under impact loads are compared and analyzed. Impact tests are carried out to test the dynamic mechanical properties of the internal energy-absorbing column, and test data including the first peak value of support reaction force, the first peak value of liquid pressure, and the stress peaks on the outer wall of the first-stage cylinder lower cavity and sliding cavity cylinder at key node moments are obtained. The test data from the impact tests are basically consistent with the results of the simulation, with an error rate of less than 10%. The results show that the extension ratio of the internal energy-absorbing column is significantly higher than that of the external structure. Under the same impact conditions and total height, the initial peaks of support reaction force of the internal and external energy-absorbing columns are 2 216.00 kN and 2 225.78 kN respectively, and the effective energy absorption from the start of impact to the densification moment of the energy-absorbing device is 167.87 kJ and 173.03 kJ respectively. The two types of columns have comparable energy absorption effects during the crushing deformation of the energy-absorbing device. However, compared with the external energy-absorbing column, the maximum support reaction force, maximum liquid pressure, and maximum stress on the outer wall of the cylinder of the internal energy-absorbing column are reduced by 31.61%, 32.97%, and 29.59% respectively. These results indicate that the structural design of the internal energy-absorbing column is feasible and that it has excellent impact resistance performance.