Abstract: A reasonable islanding operation strategy is of great significance for power restoration as well as system resilience enhancement when major failures occur in the distribution network. Therefore, the problem of utilizing traditional contact lines and emerging distributed generation (abbr. DG) to restore integrated power to outage areas in the distribution network was profoundly studied. Firstly, the integrated power restoration problem was uniformly simplified as a generalized DG-based islanding problem by equating the contact lines to virtual DGs. Secondly, to adequately quantify the risk of islanding operation during failure hours, the islanding operation risk indicators were defined from the perspectives of power balance and voltage stability, and a dynamic constraint method for islanding operation risk was proposed based on the opportunity constrained optimization model. Subsequently, a generalized dynamic islanding strategy for distribution networks considering operational risks was proposed. This strategy can dynamically adjust the island range based on risk factors such as DG output, load timing changes, and node voltage levels, maximizing the utilization of DG resources during fault periods while ensuring the stability and sustainability of island operation. In allusion to the problem of high difficulty in solving the dynamic islanding strategy, the improved branch-and-bound method in combination with the heuristic algorithm was used to solve and dynamically modify the islanding strategy to ensure the rationality and timeliness of recovery decisions under emergencies. Finally, simulation experiments and analysis were carried out based on a 40 node distribution network example to verify the effectiveness of the proposed method.