In this study, we have investigated CuO doping effect on PZT-PZNN thick film for lower temperature sintering of multi-layer structure energy harvesting system. We prepared 0.69PZT-0.31PZNN powder, slurry, and green sheet to manufacture thick film ceramics with different doping amount of CuO. Various amount of CuO (0, 1, 2 and 3 mol%) were inserted into piezoelectric material composition of (Zr0.47Ti0.53)O3- 0.31Pb {(Ni0.6Zn0.4)1/3Nb2/3}O3. Laminated thick films with thickness of 0.310 mm were sintered at 900°C. Microstructures were investigated by using SEM and XRD. Also, dielectric property of sintered samples was measured by using d33 meter. As results, dielectric permittivity increases as CuO doping amount increases, which led to decrease in resistance and increase in capacitance value. CuO doping amount of 2 mol % was found to be the optimized point with the highest d33 value. This was explained by SEM images. The SEM images showed the increasing grain size as the CuO doping amount increase, and as the doping amount was 2 mol % or higher, secondary phase was observed in XRD. After measuring and analyzing the CuO doped samples, 2 mol% CuO doped PZT-PZNN thick film was placed on a SUS301 substrate to perform as a unimorph cantilever type energy harvesting system. First, the resonance frequency was observed in 39 Hz with 10.4V. At the resonance frequency, the impedance matching was found at the 2 M Ω, which the output power was calculated as 8 μW. This output power was then calculated as 0.267 mW/cm3.