Gas hydrate (GH) is a kind of solid energy resource with huge reserve. Stratum instability (such as marine landslide) may be caused by hydrate dissociation due to the softening of stratum and the buildup of excess pore pressure. In this paper, a centrifuge experiment was conducted to study the evolution of stratum instability during hydrate dissociation. The hydrate dissociation zone expands from the heating source in hydrate bearing sediment (HBS). The pore fluid pressure increases significantly accompanying the slow seepage and soil layer's softening and deformation. Large horizontal displacements and vertical displacements can be observed and increase with the expansion of hydrate dissociation zone. The results can be used for the verification of numerical simulations and a reference for engineering design.