Biocomposite materials have the potential to address some of the health and environmental issues we face today. These materials are made from renewable resources. In addition to their environmental benefits, biocomposites also offer advantages over traditional synthetic composites in terms of their mechanical properties and durability. For example, some biocomposites have been shown to have high strength-to-weight ratios and excellent resistance to fatigue and impact This work shows the results of a numerical analysis of the damping characteristics of a bio-composite with and without a Viscoelastic Layer (VL). The insertion of this layer has a significant influence on the vibration behavior, bending stiffness and damping factor. The inserted viscoelastic layer in the middle plan of the composite is natural rubber and the external layers are flax fibers in PLA matrix composite. The composite is produced by the additive manufacturing technology. The aim of this article is the comparison of the results of numerical and the experimental vibration behavior of composite material: Flax/PLA composite and viscoelastic composite. This works has guiding significance for the calculation and application of elastic viscoelastic elastic sandwich structure.