In view of the high difficulty and limitations in the current microcellularization technology of woodplastic composite materials, a continuous extrusion microcellularization test platform suitable for the material properties was established by optimizing the screw geometry and designing the foaming mold. The internal bubble structure characteristics of the samples under different processing conditions were observed to reveal the gas bubble derivation behavior and morphological evolution law in the extrusion process, thereby achieving effective size parameter control. The results show that using the Celuka foaming mold and enhancing the screw mixing ability can help obtain the desired pressure drop parameters to achieve the microcellularization of wood-plastic composite materials in the foaming process. In addition, due to the influence of the melt flow state, bubbles undergo certain deformation behavior during growth, and enhancing the melt strength can help improve its structural stability. At the same time, by adjusting the process parameters such as foaming temperature and screw speed, the load-bearing capacity of the samples can be significantly improved, and the bubble size and distribution density can be optimized to 87.6 μm and 2.3×10⁴ cm^-3, respectively.