A switching device, a Peripheral Component Interconnect Express (PCIe) system, and a switching system, where the switching system includes a first switching device and a second switching device. The first switching device and the second switching device are coupled using a network. The first switching device includes a plurality of PCIe upstream ports configured to connect to at least one host, the second switching device comprises at least one PCIe downstream port configured to connect to at least one input/output (I/O) device, and the second switching device is configured to receive a first data packet from the first switching device using the network, convert the first data packet to a second data packet complying with a PCIe protocol, and transmit the second data packet to a target I/O device of the second data packet.
