During the shear test, maintaining the stability of the shear plane for specimen is the key to obtain the shear test data with practical value, and in the axial shear test of tubes, the semi-mandrel structure that applies shear force is an important factor affecting whether the tubes can be in the best shear state. Therefore, for thin-walled 5052 aluminum alloy tube with the outer diameter of Φ50 mm and the wall thickness of 1.2 mm, the axial shear loading research was conducted, and the influences of the tube axial shear device with or without a guide structure on the stress state of shear zone were compared and analyzed. Furthermore, the strain distribution in the shear zone was measured by the digital image correlation system. The results show that the shear strain in the center of shear zone for the axial sheared specimen is the smallest, and gradually increases towards the two ends of shear zone. After adding the guide structure, the width of shear zone decreases, the deformation is more concentrated on the preset shear plane, and the difference between the end and center point of shear zone decreases, which improves the uniformity of shear strain distribution and the test accuracy of shear mechanical properties.