The invention discloses a method and device for determining power supply reliability, a storage medium and a processor. The method comprises the following steps: determining each network group model in a power grid, wherein at least one network group model exists in the power grid and the network group model consists of equipment nodes with connection relationship; after the network group model isin failure, acquiring time information needed by failure recovery of the network group model, wherein the time information comprises the power-off time of each piece of equipment node in the networkgroup model; and according to the time information, determining the power supply reliability index of the power grid, wherein the power supply reliability index is used for reflecting the power supplyreliability degree of the power grid. The technical problem in the prior art that the method for determining the reliability of the power grid is large in computation burden and low in precision is solved.