The invention relates to the cloud storage field, and discloses a performance improving data processing method in a cloud storage system. The performance improving data processing method relates to a metadata management system, an online data storage system, a near line data storage system, an off-line data storage system and a client terminal. Only control signal transmission is carried out between the metadata management system and the client terminal, storage data flow transmission is not carried out between the metadata management system and the client terminal, and the storage data flow transmission is carried out between the client terminal and the online data storage system. Data are autonomously transmitted among different devices in the cloud storage system so that the devices with different configurations can be effectively used, and the whole use ratio of the cloud storage system is improved. By means of data segmentation, concurrency of data reading and writing is improved, the IOPS and the bandwidth are improved, the reading and writing time is shortened, and the performance is improved. Improvement is carried out on an existing cloud storage system device, the process is completely implemented through software on the basis that hardware accesses are in good conditions, and the implementation and achieving difficulties are small. The performance improving data processing method can be popularized and used on a large data platform.