As an important kind of energy source, radioisotope batteries are attracting more and more academic researchers and people from industry due to the high power density, long lifetime (equal to half life of the radioisotope source), outstanding reliability, without maintenance, miniaturization and wide application compared with traditional dry batteries, chemical batteries, fuel batteries and solar batteries. Radioisotope batteries have been developed for more than 15 species since the first β battery invented by Henry Mosley in 1913. Based on a Brayton cycle Radioisotope Power System and a PZT-5H (Pb(ZrxTi1-x)O3, 0≤x≤1) unimorph, the piezoelectric nuclear battery driven by the jet-flow (PNBJ) is demonstrated in this work. The PZT-5H unimorph replaces turbine and utilizes high speed nitrogen jet-flow heated by the decay energy of radioisotope to output electrical energy. Over 0.34% energy conversion efficiency for the PNBJ is obtained at the flow of 2.26 × 10−3 m3/s and room temperature on half plane. The PNBJ can be used in low power microelectronics and microsystems, like electronic watch, AC-LED (alternating current light-emitting diode), and sensors. We believe that the researches and applications of PNBJ will be much attractive with the breakthroughs of preparation technology made by academic and industrial world.