A failover method, apparatus and system to implement fast failover between a primary processor and a secondary processor, where the method includes receiving, by a second device, a transaction processing packet, where the transaction processing packet includes processing information about access of a host to a peripheral component interconnect express (PCIe) device, the processing information is used to describe information required for resuming a transaction when the transaction is interrupted, the second device further stores topology information of the PCIe device, and a driver for the PCIe device is loaded to the second device, and when detecting that the first device fails, continuing to process, by the second device according to the topology information, the driver, and the processing information, the transaction that is about the access of the host to the PCIe device and is being processed when a first device fails.