Piezo-damping epoxy-based composites containing various amounts of multi-walled carbon nanotubes (CNT) and piezoelectric lead zirconate titanate (PZT) were prepared, and their performances were investigated. The composites exhibited a percolation threshold in the range of 1-1.5 g CNT per 100 g epoxy, in which a continuous electro-conductive network formed. Dynamic mechanical thermal analysis reveals that the loss factors of the composites were improved by incorporation of the PZT and the CNT at above critical electrical percolation loading. Based on this new type rigid piezo-damping material, the PZT contributes to the transformation of mechanical noise and vibration energies into electric energy, while the CNT serve in shorting of the generated electric current to the external circuit. Thermal stability and mechanical properties were also improved by incorporating these two fillers. An optimum formulation for the rigid piezo-damping materials can be designed on the basis of the results of this study.