Based on finite element numerical simulation technology, a method of calculating the load-carrying capacity of wood-plastic composite pallets with irregular cross-section was put forward. Firstly, an irregular section beam model of wood-plastic composites was established by using the method of self-defined cross-section beam element. Secondly, based on the irregular section beam model, a pallet structure model was established and the bearing capacity was calculated. Finally, the numerical calculation results were verified with the experimental results. The results showed that the numerical analysis results were in good agreement with the experimental results. The accuracy of numerical analysis method could meet the engineering requirements. Being applied to the research and development of wood-plastic composites and products with complex cross-section shape, the method could be cost saving and shorten the research and development cycle.