Bound states in the continuum (BICs) are localized states within the radiative continuum that exhibit high quality-factor (Q-factor) resonance, which significantly boosts light-matter interactions. However, out-of-plane radiation losses can arise from inherent material absorption and inevitable technological imperfections during fabrication process. Merging BICs have been introduced as a solution to address the issue of out-of-plane radiation losses. By merging BICs, it is possible to expand the area of high Q-factor resonance in momentum space, thereby enhancing the system's robustness against external perturbations. However, achieving this enhancement is contingent upon altering the geometrical parameters of the structure, which inherently restricts its dynamic tunability. Here, we propose an emerging approach that integrates phase change materials (PCMs) into photonic crystal slabs (PCs) metasurface, enabling dynamically tuning of merged BICs. By utilizing low-loss Sb