Achieving accurate locating of perforating arteries (PAs) has great clinical value in various biomedical applications, such as free flap transfer. However, the anatomical variability of these arteries presents a major challenge in PA locating, and existing methods have various disadvantages, limiting their applications. Here, we propose a reusable and flexible hydrogel biosensor array for noninvasive, precise, and efficient PA locating. Particularly, we develop electrically responsive hydrogels to establish rapidly detachable device/hydrogel interfaces, endowing the reusability of the biosensor array. Meanwhile, the adhesion of hydrogel/skin interfaces is also enhanced to facilitate high-fidelity signal acquisition. By analyzing the photoplethysmography (PPG) infrared (IR) signals, the biosensor array can accurately and responsively locate PAs across different types of free flaps in clinical cases, outperforming existing techniques. This biosensor array represents a promising platform for PA locating. The strategy of hydrogel interface design paves the way for the development of reusable flexible electronics in biomedical applications to avoid cross-infection and reduce device costs.