The invention provides a data operating method of redundant arrays of an independent disk and a device; wherein the method comprises the following steps: creating a logic unit based on RAID and dividing the logic unit into multiple grain size intervals, and carrying out striping processing based on the grain size intervals; before carrying out write operation on the logic unit, judging whether the sizes of the strips to be written into the grain size intervals are matched with the current values of strip parameters; if not, adjusting the sizes of the strips to be written into the grain size intervals according to the current values of the strip parameters and carrying out write operation according to the adjusted sizes of the strips; or, directly carrying out write operation according to the sizes of the strips to be written into the grain size intervals; wherein the strip parameter has an initial value and is updated according to the writing data quantity of write operation on the logic unit. According to the data operating method, the data read/write performance of the RAID can be improved.