With widespread digital work and sedentary lifestyles, polyarticular musculoskeletal disorders (MSDs) have become a global health concern and is gradually intensified by the lack of real-time posture monitoring. Existing systems face challenges in compliance, multi-site coordination, and energy use. This study presents a flexible, wearable MWNT/PVDF electrospun membrane-based triboelectric nanogenerator (MEM-TENG) with a hollow array structure for real-time MSDs monitoring. The polyvinylidene fluoride (PVDF) nanofiber membrane doped with multi-walled carbon nanotubes (MWNTs) is fabricated to enhance β-phase formation and electrical output of the device. The arrayed hollow structure supported by a foam-like double-sided adhesive is designed for controllable contact and effective sensing. Polyurethane encapsulation is performed to ensure flexibility, waterproofing, and skin comfort. Notably, the MEM-TENG achieves a high sensitivity of 6.67 V·N −1, enabling the precise detection of subtle biomechanical stimuli across multiple body sites. The application experiments demonstrate that the MEM-TENG is capable of wireless real-time monitoring of multiple joint postures, followed by intelligent diagnostics based on AI-driven data analysis. The proposed device demonstrates notable advantages over conventional technologies in terms of mechanical adaptability, spatial resolution, and self-powered operation. It offers a promising solution for multi-site synchronous monitoring, enabling early diagnosis, personalized rehabilitation, and smart musculoskeletal health management.