In order to explore the failure mechanism of lateral shear damage of stainless steel core plate for highway engineering, and to solve the problem of lack of test data support in the actual engineering needs, this study carried out two groups of different specifications of 2×3 core plate sandwich structure specimens straight compression shear test, and constructed a finite element numerical model to verify and analyze the test results. The test results show that the stainless steel core plate shear test curve presents a typical three-stage evolution characteristics, divided into elastic stage, elastic-plastic stage and plastic damage stage; the structural failure mode is manifested as the pipe end wrenching edge region corner and pipe end pressure region preferentially occurs local buckling, followed by the core pipe gap at the panel of local instability bending; the shear performance of stainless steel core plate with the increase of the thickness of the panel is significantly improved, 8mm thickness of the core plate shear strength, 8mm thickness of the core plate shear strength. The shear performance of the stainless steel core plate increases significantly with the increase of panel thickness, and the shear strength, extreme shear strength and shear modulus of elasticity of the core plate with 8 mm thickness are improved by 39.4%, 15.7% and 32.7%, respectively, compared with that of the core plate with 6 mm thickness. The numerical simulation is basically consistent with the test results, effectively verifying the accuracy of the finite element model parameter selection and modeling scheme. The lateral shear load capacity of the stainless steel core plate is greatly affected by the relative relationship between the panel thickness, core tube wall thickness, and outer diameter, etc. Its shear ultimate load capacity increases significantly with the increase of panel thickness, core tube wall thickness, and outer diameter, and decreases slowly with the increase of core tube height and spacing.