Efficient and safe exploitation of gas hydrate can be significantly promoted by reservoir stimulation, with the key lying in the physicochemical mechanisms and geomechanical responses during post-stimulation production. Conventional simulation methods can easily predict gas production from hydrate reservoirs, but often neglect the mechanical response during extraction. To address this limitation, THMC(thermal-hydraulic-mechanical-chemical) coupled model was established to simulate gas hydrate reservoir recovery via fracturing combined with caprock sealing. The evolution of gas production and mechanical response with different stimulation parameters was elucidated. The results show that when the middle horizontal well deployment scheme is adopted, the three-year cumulative gas production is the largest and the subsidence is the smallest, demonstrating optimal development benefit. Fracturing can significantly enhance gas production. As the sealing layer moves closer to the hydrate layer, gas production increases and subsidence decreases. With increasing sealing layer length, gas production initially increases and then stabilizes, while subsidence shows the opposite trend. The low-permeability sealing layer hinders downward cold-water migration from the overburden, reconstructs the pressure gradient field of the entire formation, thereby enhancing production and reducing subsidence. The thickness of the sealing layer has little effect on gas production, and the reduction in subsidence is attributed to the mechanical strength of the sealing layer itself. In conclusion, this study helps to understand the gas production and mechanical response mechanisms of hydrate-bearing sediments during fracturing combined with caprock sealing under horizontal well depressurization, providing a simulation basis for the design of hydrate extraction schemes.