Metasurfaces, leveraging custom-designed specific electro-magnetic fields and strong light-matter interaction enhancement, have shown great potential in biosensing. However, metasurface-based sensing technologies focusing on the single resonant mode which can only achieve single capability, hindering the development of integrated biosensing technologies. Based on symmetry breaking, this paper proposes a dual-mode optical platform that combines over-coupled modes and bound states in the continuum. Benefiting from the high-Q BIC mode, the platform exhibits ultrahigh sensitivity for refractive index sensing. Meanwhile, by utilizing the strong field localization of over-coupled modes, it achieves fingerprint spectral feature extraction over an ultra-broad bandwidth. The proposed metasurface shows excellent potential in biomolecular detection and is expected to provide a new paradigm for high-precision biosensing.