With the growing demand for applications in disease diagnostics, bioanalysis, and health monitoring, developing efficient biosensing systems for fast detections and trace analysis of biomarkers is of great significance. In this work, an embedded optofluidic biosensing platform is proposed, which consists of asymmetrical core-offset optical fiber (ACOOF) structure, microfluidic chip and photoelectric detection system. In particular, by introducing the concept of optical fiber bridge, an ACOOF structure is designed to improve the optical coupling efficiency and reduce the limit of detection (LOD) of the developed sensor. On this basis, the human epidermal growth factor (EGF) was detected by constructing optofluidic chip and enzyme-linked immunosorbent assay (ELISA) kit. The LOD was 0.587?pg/mL. Leveraging the developed biosensing platform integrated with our chip, we achieved trace analysis with high specificity, as demonstrated by the measurement of interleukin 1α (IL-1α) with a low LOD of 43.3?fg/mL. Monitoring these two biomarkers is important for early cancer diagnosis. Beyond this, this novel platform has the potential for a range of applications, including disease diagnosis and management, bioanalysis, and health and environmental monitoring, with a focus on alternative biomarker targets.