The present invention discloses a PCI-Express multimode expansion card comprising a PCI-Express interface port for insertion into a PCI-Express slot of a motherboard, a PCI-Express expansion port, a USB expansion port, and a jumper circuit connecting the PCI-Express interface port and the two expansion ports. The PCI-Express expansion port provides expandability by allowing the attachment of a PCI-Express interfaced peripheral device, and the USB expansion port provides expandability by allowing the attachment of a USB-interfaced peripheral device. As such, a single PCI-Express multimode expansion card inserted into a PCI-Express slot configured on the motherboard can be used to attach two peripheral devices with different interface, thereby achieving the function of multimode expansion.