A storage expansion apparatus and a server, where the storage expansion apparatus includes a quick path interconnect (QPI) interface module, which communicates with a central processing unit (CPU) through a QPI bus; a peripheral component interconnect express (PCIe) interface module, which communicates with the CPU through a PCIe bus; an interface selecting module, connected to the QPI interface module and the PCIe interface module separately; a home agent (HA) module, connected to the interface selecting module; and a memory controller engine (MCEng) module, connected to the HA module and the interface selecting module separately. The storage expansion apparatus may serve as a CPU memory capacity expansion device, and may also serve as storage expansion hardware of storage input and output (TO).