The invention relates to the technical field of power supply, and particularly relates to a two-stage power distribution network emergency island division method. The method comprises the steps: before a fault occurs, taking the guaranteeing of the stable transition of a system fault moment as a main target according to measurement information of a wide-area measurement system of a power distribution network, continuously solving a pre-fault island division optimization model at a certain time interval, and obtaining a pre-fault original island division scheme meeting the current state of thesystem; carrying out load increasing and load reducing correction of the original island scheme before the fault to obtain an island online division decision table, thereby facilitating real-time query at a fault moment to obtain a load shedding scheme meeting a system real-time state; after the system enters the initial island state through the execution decision table, dividing the whole power failure period into a plurality of time periods according to the estimated power failure time; taking the increase of the number of recovered loads as a target, solving the Look-ahead roll island division optimization model after the fault to obtain the latest island division scheme, and executing the latest island division scheme. According to the invention, the method guarantees the continuous power supply of a key load during the fault.