Abstract The alternating multilayered damping composites, chlorinated butyl rubber (CIIR) as damping layer and polymethyl methacrylate (PMMA) as constraining layer, were first prepared through novel multilayered co-extrusion. The damping properties of the CIIR/PMMA multilayered damping composites were investigated by dynamic mechanical analysis (DMA). The results showed that the damping peak moved to high temperature and the efficient damping temperature range was broaden with the layer number increasing. The shift of the loss peak was ascribed to the move of Rouse mode of CIIR, which was attributed to the motion of longer chain segment, but the local segmental motion was not changed. Finite element analysis (FEA) was used to simulate the distribution of shear strain in the multilayered damping composites. The FEA results exhibited that, in the temperature range between Tg-CIIR and Tg-PMMA, the shear strain occurred in the CIIR layer under vibration field, since the storage modulus (E′) of PMMA was much higher than that of CIIR. Furthermore, the average shear strain was increased with the layer number increasing.