Abstract: The hindered phenol AO-80/nitrile-butadiene rubber (NBR)/poly(vinyl chloride) (PVC) crosslinking composites were prepared and their microstructure and dynamic mechanical properties were investigated. SEM and TEM prove that the majority of AO-80 dissolve in the NBR/PVC matrix and the remnants AO-80 in the submicro-size particles distribute in the matrix. The DSC and XRD results illustrate that AO-80 in the matrix exists in an amorphous form. The results of DSC and DMTA prove that strong intermolecular interactions are formed between AO-80 and NBR/PVC matrix. All the AO-80/NBR/PVC crosslinking composites have only one tanδ peak, which displays the excellent compatibility between the AO-80 and the NBR/PVC matrix. More importantly, the tanδ peaks of the crosslinking composites shift to the higher temperature with increasing of the AO-80 amount in the composites, and the tanδ value of the crosslinking composites obviously synchronously increases. The chemical crosslinking of the composites results in considerable tensile strength. The high damping and mechanical properties endow the composites with a potential and promising application future in engineering.