The invention discloses a method for hierarchically caching read-write data in a storage cluster, relates to the technical field of cloud computing, and is implemented on the basis of a back-end storage cluster, a first-stage cache, a second-stage cache, an api gateway, a log file system and an application program. The back-end storage cluster manages the original data while the first-stage cache stores the hotspot data. Hot spot data is divided into different pools, the second-stage cache extracts the poll data into segments according to indexes and stores the segments, and the api gateway processes the requests in a unified mode. When the application program initiates a read request, the api gateway processes the request and publishes the request to the second-stage cache, the second-stage cache searches related segments and locates the related segments to the pool, or, if the related segments are not found, a segment missing request is further initiated to the first-stage cache, and after related information still cannot be found, the second-stage cache continues to search in a back-end storage cluster; when the application program initiates a write request, the api gateway processes the request and writes the request into a log file system, and Flush enters a back-end storage cluster after a transaction is completed. According to the invention, time delay can be greatly reduced.