This research is aimed to evaluate the feasibility and efficacy of a piezoelectric thinfilm (PETF) based, implantable and self-powered monitor for blood pressure (BP) through theoretical, in vitro and in vivo studies. A 3-dimensional simulation model revealed that both the stresses of aorta wall and the generated electric potential by device were proportional to systolic BP. With an in vitro testing system, an excellent linearity (R 2>0.99) was achieved between the peak output voltage of device and flow pressure, with a high-sensitivity of 173mV/mmHg which is significantly higher than reported results. A maximum instantaneous power of 2.3μW was reached in vitro, indicating a robust self-powered capability. Excellent stability of the device was also achieved for more than 50,000 operating cycles. In vivo experiment was carried out in adult Yorkshire porcine. A favorable linearity (R 2=0.971) with a sensitivity of 14.32mV/mmHg was obtained, and the device output a maximal instantaneous power of 40nW in vivo. Based on these characteristics of the device, we established an implantable, self-powered and visualized blood pressure monitoring system for in vitro and in vivo demonstration. A hypertension status could be alarmed visually in real-time using this system, without a built-in battery. Integrated with a coupling function of energy harvesting and biomedical sensing, this new technique shows a promising perspective in the field of the implantable healthcare monitoring.