The invention discloses a method and device for changing RAID attributes, and belongs to the technical field of storage. The method comprises the steps that an RAID set 1 is established on a source RAID set and a target RAID set; the RAID set 1 is mapped to a client terminal; data in the source RAID are copied to the target RAID set according to target attributes; after all the data are copied, the target RAID set is mapped to the client terminal. According to the method, the RAID set 1 is established on the source RAID set and the target RAID set, the operation is easy and convenient, and services are provided by the RAID set 1 for the client terminal, so that the large influence on the IO performance cannot be caused in the data copying process, and service processing of the client terminal is not required to be suspended; when an abnormal situation happens, the data loss cannot be caused, and reliability is improved; furthermore, when the data copying is completed, the target RAID set is mapped to the client terminal, the aim that the attributes of the RAID set are changed into the target attributes is achieved, and the method is applicable to various target attributes and has high applicability.