Abstract: To investigate the effect of aspect ratio on the strength and failure mode of rock sample under the combined dynamic and static loading conditions, the basic law of the stress wave propagation in split-Hopkinson pressure bar (SHPB) test was initially elucidated based on the rock dynamics theory. Subsequently, the ANSYS/LSDYNA finite element numerical simulations were conducted on six groups of rock samples with different aspect ratios under the combined static and dynamic loading. The evolution laws of stress-strain responses and failure patterns were further analyzed. The results show that the stress-strain curves of the rock samples under the combined static and dynamic loading can be roughly divided into linear elastic stage, failure stage and post-peak stage. As the aspect ratio n increases, the concave phenomenon at the failure stage becomes more obvious, and the stress-strain curve rebounds at the post-peak stage once the aspect ratio n exceeds 0.8. When confining pressure is constant, the peak stresses of rock samples under different axial compression generally increase with the increase of the aspect ratio. When the axial compression is set as 20 MPa, a threshold of the confining pressure exists, where the peak stress of larger aspect ratio of rock sample is higher as the confining pressure is below it. However, it hardly varies with the aspect ratio when the confining pressure is over this threshold. An increase in the confining pressure can suppress the effect of the aspect ratio on the peak stress. Under the combined different static and dynamic loading,the rock samples mainly exhibit shear failure, with fragments falling off at the edge of the end faces and shear cracks observed on the sides. As the aspect ratio increases, the failure degree of rock samples gradually decreases and the number of lateral shear cracks tends to decrease.