<p>Conventional metasurfaces are usually constrained by static material compositions and geometric configurations, exhibiting limited capabilities for dynamic electromagnetic applications. On the other hand, although the dynamic and reconfigurable metasurfaces have been extensively studied, their single-dimensional modulation mechanisms often fail to address the requirements of complicated electromagnetic environments. To address these limitations, a significant multifunctional terahertz metasurface from the integration of vanadium dioxide, graphene, and photosensitive silicon is proposed in this work. This unique design combines the strong field-localization characters of bound states in the continuum (BIC) and the advantages of the terahertz spectrum to achieve simultaneous modulations in terahertz electromagnetic wave absorption and sensing function. Remarkably, the BIC mode with an infinite quality factor can transform into a quasi-BIC (QBIC) mode with a finite quality factor by adjusting the system’s asymmetry; at the same time, the synergistic modulations of conductivity, optical response, and phase transition can overcome the limitations of single-dimensional tuning. Furthermore, adjusting the conductivity of VO₂ in the device enables a switch between a BIC mode and a narrowband absorption character. Based on the narrowband absorption character, a theoretical framework for high-sensitivity dielectric sensing with an excellent 671&#xa0;GHz/RIU sensitivity is further established. The proposed multi-mechanism synergistic tuning strategy offers novel insights into the development of dynamically adaptable terahertz devices and ultrasensitive sensors.</p>