This research is aimed to evaluate the feasibility and efficacy of generating electric power utilizing the pulsating energy of ascending aorta with a flexible and implantable piezoelectric generator (PG) through in vitro and in vivo studies. In the in vitro study, the max output voltage (Vmax), current (Imax) and power (Pmax) of the PG were 10.3V, 400nA and 681nW respectively. The quantity of electric charging by one pulse was about 7–9nC. Factors affecting its output performance were investigated with single variable experiments. We further implanted the PG to wrap around the ascending aorta of a porcine to investigate the output performance in vivo. The Vmax and Imax of the implanted PG were 1.5V and 300nA under the heart rate of 120bpm and the blood pressure of 160/105mmHg. The instantaneous output power was 30nW with a long-lasting duration of 700ms and 77.8% duty ratio. The implanted PG could charge for a 1μF capacitor to 1.0V within 40s.