Abstract: Traditional THz devices have long been constrained by radiation losses caused by the diffraction limit, with quality factors generally below 10⁵, severely limiting communication and sensing performance. To address this technical bottleneck, this study proposes a silicon-based metasurface design with C_6v symmetry based on the theory of topological photonics to achieve topologically protected high-Q factor resonance in the terahertz (THz) frequency band. By constructing a triangular lattice photonic crystal slab, cylindrical etched holes are introduced within the unit cell to preserve symmetry, and ideal magnetic conductor boundary conditions are employed to separate TE modes, thereby incorporating the topological protection mechanism of bound states in the continuum (BIC) into the THz frequency band. The results show that the Q factor reaches 10¹⁰ at the Γ point, and the BIC is located at the center of the polarization vortex in the far-field radiation, verifying the BIC mechanism and its topological properties. The simulation results are excellent. Ultimately, the Q factor is improved by several orders of magnitude compared to traditional devices, and the topological protection mechanism can significantly suppress the impact of processing defects and environmental disturbances on resonance performance, providing a new paradigm for low-loss communication devices, optical programmable technology, and quantum light source design.