A cloud storage method and a cloud storage system are provided. The method includes: generating, by a QKD system on a terminal side and a QKD system on at least one cloud server side, at least one quantum key over a quantum network; sending, by the QKD system, the at least one quantum key to the key management terminal for storage; and obtaining, by a cloud storage client, the at least one quantum key from the key management terminal, and processing the at least one quantum key to generate a combined key by a predetermined encryption algorithm.