Abstract: Hydrate dissociation in marine deposits may cause large disasters. Experiments are carried out to study the failure conditions and modes caused by the dissociation of hydrate. A rectangular model box and a cylindrical model box are designed to simulate the two-dimensional and one-dimensional conditions respectively. It is shown that kinds of failure modes, including slowly sliding and settlement, layered destruction and burst, occur with the thermal dissociation of hydrate happened fast or slow and for different hydrate deposit and cover deposit (such as the heterogeneity of the deposit, permeability of the cover layer). Each kind of these failures is a severe threat to engineering.