The work aims to study the mechanical properties of a plant fiber foaming material and establish the visco-elastic plastic mechanical model. The stress-strain curve of the plant fiber foaming material was obtained in the static compression test conducted with universal material tester. The mechanical model of the plant fiber foaming material was established. Regression analysis and parameter identification of the experimental data were carried out with SPSS software. Finally, the agreement between the model curve and the experimental data was compared and analyzed. There were three stages of deformation of the plant fiber foaming material, namely, elastic stage, visco-plastic stage and crushing stage. The visco-elastic plastic model of the plant fiber foaming material could be made up of a linear spring element, a nonlinear spring element, a viscous element and a plastic element. In the elastic stage, the modulus of elasticity of the plant fiber foaming material was 5.873 MPa. In the visco-plastic stage, the mechanical model of the plant fiber foaming material could be expressed by a cubic function, wherein the cubic term, the quadratic term, the linear term and the constant term were 9.155, −9.1, 3.608 and 0.136, respectively. The plant fiber foaming material is a kind of visco-elastic plastic material whose theoretical model can be expressed by a cubic function, and the experimental data well agree with those of the theoretical model.