Wearable sweat sensing technologies have attracted widespread attention for their noninvasive health status monitoring. However, simultaneously achieving high-performance sensing, breathability, and biodegradability is an extreme challenge. Herein, a multifunctional wearable electrochemical biosensor based on a patterned Janus fabric is designed to analyze glucose in sweat continuously. The glucose sensing fiber electrodes have a low-cost but highly efficient glucose-sensing element, cuprous oxide (Cu₂O), and the biosensor achieves ultra-high sensitivity (8650.3 μA mM⁻¹ cm⁻²) and long-term stability (retaining 95.8% of its initial value after 35 days). The biosensor also features outstanding sweat collection efficiency and biodegradation, satisfying the practical application requirements. Meanwhile, a wearable glucose intelligent early warning system is developed based on this multifunctional biosensor integrated with signal processing and wireless communication, combined with data analysis software. In volunteers, this system enabled the real-time monitoring of glucose levels and activated the warning feedback function in an emergency. The integrated multifunctional wearable system demonstrates the ability to intervene remotely for early disease detection and health management.