A method and system for taking over devices are provided. In a solution, a first control board first performs topology discovery on a Peripheral Component Interconnect Express (PCIE) bus, and reserves resources for a Switch (SW) where a NON-Transparent (NT) bridge is located and devices connected to down ports of the SW according to a set resource reservation policy when the topology discovery proceeds to the NT bridge, where the SW and the devices are currently controlled by a second control board. After the SW and the devices are taken over from the second control board, the resource reserved in advance may be allocated to the SW and the devices, so that the devices that are taken over operate normally under control of the first control board. Dual control is implemented through direct taking over devices, and a response speed for processing a device request is improved.