Rubber polymers as acoustic damping materials are widely used in industrial sectors. However, there is still no theoretical method to rapidly predict the damping properties of rubber polymers. Here we propose a theoretical method for the fast calculation of damping loss factors in rubber polymers. Molecular dynamics simulations were employed to construct the optimal configuration of internal polymer chains with density as the descriptor in order to calculate the mechanical properties and thus the damping loss factors. The acceptable difference between the calculated and experimental damping loss factors shows that the proposed method is efficient to predict the intrinsic damping properties of rubber polymers. Through studying the relationship among composition, microstructure, and the damping property, we found that the carbon-carbon skeletal chains with lateral methyl groups produce high damping properties.