Abstract: According to the structural characteristics of the plant single cell, taking two-dimensional problem as the research target, the mechanical model for polyhedron single cell was established through which mechanical models for macroscopical plant and many cells could be established expediently. The calculational formula for cell compressive force was obtained expressed by cell girth and by node coordinate and displacement of plant cell mechanical models. The calculational method for plant cell compressive force was obtained that was convenient for theoretical analysis and numerical calculation. Consequently, a method for calculating the cell compressive force was provided, which can be used to analyze the mechanical behaviours of plant tissues and cells at cell levels.