A method of improving the Input/Output (I/O) performance of a Redundant Array of Independent Disks (RAID) system using a Matrix Stripe Cache (MSC). The method includes a first step of generating a rxw matrix, that is, a read and write matrix, present before row combination, through a unit MSC that will perform writing on a disk, a second step of generating a rxw matrix, that is, a final read and write matrix, from the rxw matrix present before row combination, which is generated at the first step, through row combination, and a third step of performing reading based on the row-combined rxw matrix generated at the second step, performing an XOR operation on the row-combined rxw matrix on a row basis, and performing writing on the row-combined rxw matrix on a column basis.