In this work, the damping mechanisms of C5 petroleum resin/chlorinated butyl rubber composites were studied by experimentation, molecular dynamics (MD) simulation, and statistical analysis. At the macro level, damping parameters, including glass transition temperature and effective damping temperature region, loss modulus, contact angle, relaxation time, and activation energy were obtained through dynamic mechanical thermal analysis, drop shape analysis, broadband dielectric relaxation spectroscopy, and differential scanning calorimetry. At the micro level, four intermolecular interaction parameters, including binding energy, fractional free volume, mean square radius of gyration, and mean square displacement, were calculated by MD simulation. The quantitative relationships between the damping and intermolecular interaction parameters were obtained by linear regression analysis. The results are expected to provide useful information for understanding damping mechanisms and a quantitative tool for predicting the damping properties of rubber composites.