A signal switch apparatus includes a signal switch component, which is connected to a interrupt controller, a high level signal, and two PCI slots. Only when the SCSI card is inserted into the first PCI slot, is the interrupt signal sent by the SCSI card transmitted to the interrupt controller through the signal switch component. When the RAID card is inserted into the first PCI slot and the SCSI card is inserted into the second PCI slot, the interrupt signal sent by the SCSI card is transmitted to the RAID card through the signal switch component.