A method for calculating an identification threshold to distinguish cold data and hot data performed by a storage control server, wherein the storage control server is connected to multiple storage nodes, thereby forming a storage system, wherein each one of the storage nodes comprises a hot data storage medium and a cold data storage medium and each storage node stores a plurality of data blocks, wherein the method comprises: • sending an IO statistical information query command for the plurality of data blocks to each storage node (step 201); • receiving IO statistical information from each storage node, wherein the IO statistical information comprises at least one IO count field value, and a quantity of data blocks with an IO count value being in each count range that are on each storage node that sends the IO statistical information is recorded in each IO count field value (step 202); • performing an addition operation on IO count field values in a same count range in the received IO statistical information of all the storage nodes, to generate an IO count statistical value corresponding to each count range (step 203); and characterised in: • obtaining, according to a total capacity of the hot data storage mediums of the multiple storage nodes, a size of the plurality of data blocks, and the IO count statistical values on all the storage nodes and when the hot data storage mediums are filled with data blocks corresponding to large IO count statistical values, a minimum IO count value in a count range corresponding to a minimum IO count statistical value in the large IO count statistical value, and using the minimum IO count value as an identification threshold to distinguish cold data blocks and hot data blocks, wherein each IO count statistical value in the large IO count statistical values is not less than an IO count statistical value in a non-large IO count statistical value (step 204); • sending the identification threshold to distinguish cold data blocks and hot data blocks obtained by means of calculation to a hierarchical storage executor of each storage node; and • delivering a cold and hot data identification command and a data migration command to the hierarchical storage executor of each storage node for migrating the hot data blocks to a hot data storage medium of the storage system and the cold data blocks to a cold data storage medium of the storage system. • sending an IO statistical information query command for the plurality of data blocks to each storage node (step 201); • receiving IO statistical information from each storage node, wherein the IO statistical information comprises at least one IO count field value, and a quantity of data blocks with an IO count value being in each count range that are on each storage node that sends the IO statistical information is recorded in each IO count field value (step 202); • performing an addition operation on IO count field values in a same count range in the received IO statistical information of all the storage nodes, to generate an IO count statistical value corresponding to each count range (step 203); and characterised in: • obtaining, according to a total capacity of the hot data storage mediums of the multiple storage nodes, a size of the plurality of data blocks, and the IO count statistical values on all the storage nodes and when the hot data storage mediums are filled with data blocks corresponding to large IO count statistical values, a minimum IO count value in a count range corresponding to a minimum IO count statistical value in the large IO count statistical value, and using the minimum IO count value as an identification threshold to distinguish cold data blocks and hot data blocks, wherein each IO count statistical value in the large IO count statistical values is not less than an IO count statistical value in a non-large IO count statistical value (step 204); • sending the identification threshold to distinguish cold data blocks and hot data blocks obtained by means of calculation to a hierarchical storage executor of each storage node; and • delivering a cold and hot data identification command and a data migration command to the hierarchical storage executor of each storage node for migrating the hot data blocks to a hot data storage medium of the storage system and the cold data blocks to a cold data storage medium of the storage system. • obtaining, according to a total capacity of the hot data storage mediums of the multiple storage nodes, a size of the plurality of data blocks, and the IO count statistical values on all the storage nodes and when the hot data storage mediums are filled with data blocks corresponding to large IO count statistical values, a minimum IO count value in a count range corresponding to a minimum IO count statistical value in the large IO count statistical value, and using the minimum IO count value as an identification threshold to distinguish cold data blocks and hot data blocks, wherein each IO count statistical value in the large IO count statistical values is not less than an IO count statistical value in a non-large IO count statistical value (step 204); • sending the identification threshold to distinguish cold data blocks and hot data blocks obtained by means of calculation to a hierarchical storage executor of each storage node; and • delivering a cold and hot data identification command and a data migration command to the hierarchical storage executor of each storage node for migrating the hot data blocks to a hot data storage medium of the storage system and the cold data blocks to a cold data storage medium of the storage system.