Wearable monitoring devices help achieve a long-term signal monitoring of the human body, which is important for human health analyses. Silver−silver chloride electrodes used for bioelectric monitoring face challenges such as gel moisture loss, inability to monitor for long periods, and skin sensitization. Herein, we report a conductive elastic composite electrode based on a thermoplastic elastomer of styrene−ethylene−butylene−styrene and conductive filler of poly(3,4ethylenedioxythiophene) and carbon black, which has excellent tensile and stable electrical properties. The conductive elastic composite electrode has a stable open circuit potential with a change of approximately 0.01 mV and low impedance (<4 × 10 −4 Ω). Simultaneously, the electrode exhibits good wear resistance and water resistance, which can be used for a long-term electrocardiogram (ECG) signal monitoring. We further investigated the integration of fiber electrodes with traditional clothing to propose a set of applications for wearable wireless ECG acquisition systems.