Provided is a method for detecting overloading of devices for load transfer in an open-loop power grid, including: constructing a power supply tree graph; determining a target device and a standby power supply; determining a target node, a target set, and one or more target subsets; for each of the target subsets, determining nodes in said target subset between which the parent-child relationship is reversed due to the load transfer, and performing overload detection on each device corresponding to one of the nodes or an edge on a path connecting the nodes; and determining two nodes between which a direct parent-child relationship is generated from nonexistence due to the load transfer, and performing overload detection on each device corresponding to a node or an edge on a path connecting a parent node of the two nodes and a common parent node.