Abstract: A three-dimensional simulating device for the stratum stability in natural gas hydrate exploitation includes a three-dimensional model located in an environmental control unit, an axial pressure control unit, and a post-processing unit. An inner cavity of the three-dimensional model is divided into a sealed simulating cavity and a sealed axial pressure sealing cavity by an axial pressure sealing piston arranged in the inner cavity. A vertical well and a horizontal well stretch into the simulating cavity. The axial pressure control unit, the environmental control unit, and a plurality of sensors in the three-dimensional model are electrically connected to the post-processing unit.