A file processing method and a storage device for storing a file in a redundant array of independent disks (RAID) are disclosed. In this method, the storage device divides received F files into multiple data blocks, and obtains a first matrix with T rows according to the multiple data blocks. Data blocks belonging to one file are located in one row of the first matrix. The storage device then writes a stripe, which consists of data blocks in each column in the first matrix and a check block that is obtained by computing according to the data blocks in the column, into the RAID. By using the file processing method, the storage device can write one file into one disk of the RAID while ensuring security of file storage, thereby achieving a better energy saving effect when the file is read.