Nowadays, the sandwich composites due to good mechanical properties, such as high strength-to-weight, are widely used in various industries such as automotive and aerospace. Structures in these industries are often exposed to high vibration that can have devastating effects in different ways. The passive vibration control method using viscoelastic materials, especially elastomers, is an approach that in many ways has been studied by researchers. In composite sandwich due to the cellular structures there are appropriate capacity for the use of viscoelastic dampers. In this regard, a review of previous works done in this field and new ideas in order to optimize the position of viscoelastic materials in the empty spaces of honeycomb panel presentated to increase damping properties with the lowest added mass. Putting elastomers in areas that are at greatest strain energy can improve vibration performance because more energy is wasted. The ideas in a honeycomb cantilevered beam were tested experimentally that the result indicated good improvement in damping charecteristics. The software modeling and simulation honeycomb beam vibration analysis was conducte using a finite element software ABAQUS. The result of the simulation were compared with the test results which showed good agreement with that. At the end, the viscoelastic layer in composite laminates were studied experimentally and in ABAQUS was simulated and also used software model to compare different situations of rubber midlayers in a composite laminate. Keywords: Honeycomb sandwich panel, Viscoelastic, Cantilevered beam, Base vibration, Composite laminate