Cloud storage system capable of achieving load balance

The invention discloses a cloud storage system capable of achieving load balance. The cloud storage system capable of achieving the load balance comprises a load monitoring service unit which is used for transmitting an application requirement to a second cloud storage station when a load of a first cloud storage station exceeds a load threshold valve. One of a plurality of service access points of the second cloud storage station is used for transmitting the application requirement to a metadata position management service unit with a relatively light load in a plurality of the metadata position management service units. The metadata position management service unit is used for assuring metadata position information which corresponds to the application according to the application requirement and obtaining the corresponding metadata from the corresponding metadata servers according to the assured metadata position information. The service access points are further used for sending the obtained metadata and the application requirement to a data document management subsystem so that the data document management subsystem executes a corresponding operation according to the application requirement. The invention further discloses a load balance method used for the cloud storage system. The cloud storage system capable of achieving the load balance is capable of improving performance of the cloud storage system.