The invention relates to the field of cloud computing, in particular to a performance-grading-based storage mechanism suitable for a cloud platform. The storage mechanism includes the steps that LUN dividing is firstly carried out inside special storage devices, and storage resources are outwards provided in an SAN mode; then, LUN devices are found and logged in to, and the storage devices are localized; logical volume groups are created on physical servers through the localized devices and shared; after sharing on all the LUN devices is completed, when virtual machines are created, the storage devices are selected according to the requirements of the virtual machines for IO speeds, and then logical volumes corresponding to the sizes of hard disks of the virtual machines are created on the volume groups corresponding to the storage devices; images of the virtual machines are injected into the logical volumes created on the corresponding volume groups, and the virtual machines are created through the logical volumes. By means of the storage mechanism, the capacity of balancing IO load storage of the whole cloud platform is provided, and the cloud platform can be scheduled on the physical servers; the storage mechanism can be used for storage management of the cloud platform.