A PCIE switch-based server system, switching method and device are disclosed. The system includes: an active PCIE switch device, where the active PCIE switch device includes a communication interface and a first PCIE switch module, and the first PCIE switch module includes at least two first PCIE ports; a standby PCIE switch device, where the standby PCIE switch device includes a communication interface and a first PCIE switch module, and the first PCIE switch module includes at least two first PCIE ports; where the communication interface of the active PCIE switch device and the communication interface of the standby PCIE switch device are interconnected, so that the standby PCIE switch device obtains switch network configuration information of the active PCIE switch device through the communication interface of the active PCIE switch device and the communication interface of the standby PCIE switch device.