A device for compensating a semiconductor memory defect suitable for a semiconductor memory is provided. The device comprises: a memory array, the memory array having a memory region consisting of a plurality of memory cells, the memory array being coupled to the address decoder circuit and the sensing circuit for storing data, if the memory array has a defect, the memory array is divided into a plurality of sub-memory regions, wherein one of the plurality of sub-memory regions is defectless, the memory array is replaced by the defectless sub-memory regions for storing data. A selection circuit coupled to the control unit, selects one of the memory region and the defectless sub-memory region to store data. A first input address buffer coupled to the control unit and the address decoder circuit has an address input port and an address output port. The address input port receives a most significant bit address signal, wherein if the memory array is defectless, the selection circuit outputs a selection signal to select the memory region to store data and makes the control unit control the address output port to output the most significant bit address signal to the address decoder circuit. If the memory array has the defect, the selection circuit outputs a selection signal to select the defectless memory region to store data and makes the control unit control the address output port to output the selection signal to the address decoder circuit.