The cascading failure often occurs in real networks.It is significant to analyze the cascading failure in the complex network research.The dependency relation can change over time.Therefore,in this study,we investigate the cascading fail-ure in multilayer networks with dynamic dependency groups.We construct a model considering the recovery mechanism.In our model,two effects between layers are defined.Under Effect 1,the dependent nodes in other layers will be disabled as long as one node does not belong to the largest connected component in one layer.Under Effect 2,the dependent nodes in other layers will recover when one node belongs to the largest connected component.The theoretical solution of the largest component is deduced and the simulation results verify our theoretical solution.In the simulation,we analyze the influence factors of the network robustness,including the fraction of dependent nodes and the group size,in our model.It shows that increasing the fraction of dependent nodes and the group size will enhance the network robustness under Effect 1.On the contrary,these will reduce the network robustness under Effect 2.Meanwhile,we find that the tightness of the network connection will affect the robustness of networks.Furthermore,setting the average degree of network as 8 is enough to keep the network robust.