Article is devoted to the definition of stress and strain states of wood filler in the composite. Were constructed diagrams of normal stresses in the sections of the composite cube perpendicular normals «a», «t», «r» limited parabola. Drawn attention to the fact that in certain studies the shrinking process of polymeric materials the authors took into account only the facts of growth strength, modulus of elasticity and the most shrinkage during curing. As a result of the introduction of the necessary data into the computer and use a special program analyzed two variants of stress and strain state in a cube of wood. Found values of the principal stresses are determined through the direction cosines of the position of the main sites, and then the relative magnitude of the principal strains.