Abstract: Islanding control, as the last one of the three defense lines for power system security, is an emergency control method when the system is subject to severe faults.Traditional islanding control fails to deal with the change of faults or operation modes of the system; adaptive islanding control methods, based on either slow coherence theory or location of oscillation center, only show effectiveness when handling systems with distinct coherence modes. This article first discussed difficulties of searching feasible cut-sets when applying conventional adaptive islanding control to a system without distinct coherence modes, such as Guangdong power grid. After that, maintaining power supply of crucial loads was selected as the target of islanding control when no distinct coherence modes exist. Then a 4-stage adaptive islanding control method including the ‘pre-screening of cut-sets,selection of initial nodes among crucial regions, expansion of nodes, examination of cut-sets’ was presented. Finally, the effectiveness of this method was demonstrated by the simulation results on Guangdong power grid.