This disclosure provides a memory system and its operation method, as well as a computer-readable storage medium. The memory system includes a memory, the physical space of which is divided into a user space and a hidden space; a memory controller coupled to the memory, and the memory controller is configured to: set a first storage block in the user space as a write acceleration cache; wherein the first storage block is a first-level storage cell mode; the write acceleration cache is configured to cache data; and set a free storage block in the hidden space as a write acceleration cache; wherein the free storage block is a first-level storage cell mode.