Abstract: When facing large scale and complex shapes situations, it is inevitable for fiber reinforced plastics (FRP) to splice two or more plies to meet the requirements. However, the complicated stress distribution within the splice structure may lead to serious safety problems. In this paper, the unidirectional carbon fiber reinforced polymer (CFRP) composite with splicing of different layers at the same location was taken as the research object. The effect mechanism of splicing on the tensile mechanical properties of CFRP composite was emphatically analyzed. The influence of ply splice on its mechanical strength was tested by tensile experiment. The damage process was recorded by camera, and the strain field near the splicing site was monitored by digital image correlation technology (DIC). The finite element model (FEM) was used to simulate and analyze the failure mechanism of the structure, and 3D-Hashin criterion and progressive damage model were used. The failure behavior of adhesive layer was described by cohesive zone model. The results show that the tensile strength of CFRP composite with the ply splice structure decreases obviously. The FEM simulation results agree well with the experimental results, which indicates the effectiveness of the model. According to the experimental results and simulation analysis, the stress concentration at the ply splice results in the separation of two splicing parts and the interlayer shear failure of splicing layer and continuous layer. After the interlaminar failure, the tensile load is completely carried by the continuous layer. Therefore, the ultimate bearing capacity of CFRP composite is determined by the number of continuous layers in the material.