The invention discloses a high-efficiency data access method of a cloud storage client. The method comprises the following steps: A, allowing the client to generate a file access request according to user operation, B, inquiring whether metadata of a file to be accessed by the file access request has corresponding cache locally in the client, executing Step D if so, and executing Step C if not, C, allowing the client to upload and download the metadata from a metadata service node of a cloud service terminal, updating the local metadata cache of the client, and finishing the process, and D, reading corresponding metadata information from the local metadata cache of the client. The invention further discloses a cloud storage client. The method and the client can improve access capability of a cloud storage system, and solve the defects of low response speed of accessing to data of the cloud storage service terminal, low concurrence efficiency and low bandwidth utilization ratio.