In the course of extracorporeal circulation (ECC), real-time monitoring of blood electrolyte levels is crucial for ensuring patient safety and improving outcomes. A continuous detection chip of blood electrolytes potassium, sodium, and calcium is developed by integrating sensor array with a microchannel for real-time monitoring instead of traditional single-point detection. The primary issue to address for continuous blood monitoring is the nonspecific adhesion of plasma proteins and blood cells to the sensors and microchannel. To enhance the antifouling capability of the detection chip, chemical doping and surface modification are applied to both the sensors and the microchannel. These treatments significantly increase the surface hydrophilicity, thereby reducing the adhesion of proteins and platelets while preserving the potentiometric performance of the sensors. By further optimizing the storage conditions, the modified chips exhibit an extended operational lifespan and robust antifouling performance. This allows for reliable long-term detection in flowing blood without signal degradation due to biofouling. The proposed method thus provides a straightforward and effective route to construct continuous electrolyte detection chips compatible with ECC platforms.