[Purposes] A new type of steel-concrete composite joint, namely the steel-concrete column box beam composite connection joint, was used in the track bearing layer of Guangzhou Baiyun Station. This paper conducts experimental and numerical simulation research to analyze the bending performance of box beam components and the stress mechanism and failure mode of the steel-concrete column box beam joint area. [Methods] Taking the beam column node of the rail bearing layer at Guangzhou Baiyun Station - steel reinforced concrete column box beam node as the research object, a 1:5 scaled model was made for testing, and a 1:5 scaled model and a full-scale model were established for finite element analysis. Through experiments and finite element analysis, the stress mechanism, failure characteristics, and ultimate bearing capacity of the node were deeply studied. [Findings] The experimental results and finite element analysis indicate that the failure mode of the node is mainly the bending failure of the box girder. Cracks first appear in the tensile area of the box girder, forming two main cracks on the side of the connection between the beam and the column. The direction of the main cracks is roughly at a 45 ° angle to the axis of the beam and column. Steel reinforced concrete columns remain in an elastic working state without any plastic deformation. [Conclusions] The research results indicate that column components have high bearing capacity. When box girder is subjected to bending failure, the column components are still in the elastic stage, which is in line with the principle of "strong column, weak beam" advocated in structural design. The finite element analysis results are in good agreement with the experimental values, effectively confirming the reliability of the numerical simulation method. This study reveals the stress mechanism and failure characteristics of steel-concrete column box beam joints, providing theoretical support for the design of steel-concrete column box beam joints and important references for safety assessment and performance improvement in related engineering practices.