ABSTRACTThis paper reviews wearable and unconstrained systems based on PVDF sensors in physiological signals monitoring. Since using wearable and unconstrained biomedical sensor systems for health monitoring is convenient and efficient, and piezoelectric polyvinylidene fluoride (PVDF) film has the advantages as flexibility, wide frequency response, low cost, easiness to fabricate, biocompatibility and light weight, many studies have focused on the PVDF film as sensors of wearable and unconstrained systems. Utilizing a modular design concept, the processing circuit of systems can be reorganized to implement different functions, so as to match different medical applications. This paper reviews key ideas and performance of the reported wearable and unconstrained systems based on PVDF sensors in physiological signals monitoring and the modular design concept. The various existing state of art practices of the wearable and unconstrained systems with PVDF sensors in measurement of physiological signals are also reviewed. And an outlook of the future about wearable and unconstrained systems with PVDF sensors in physiological signals monitoring is given.