A small-file storage optimization system based on a virtual file system in a KUBERNETES user-mode application which is applied to a target file system includes a network file system including a network file system server and a network file system client, a user-mode application mounted on a shared directory exposed by the network file system server through the network file system client, and a virtual file system including a virtual file system client and a virtual file system server. A file block creating and formatting module in the virtual file system server creates a virtual file block for storing small files on one or more object storage target devices of the target file system, and the virtual file block is mounted on the shared directory exposed by the network file system server.