A disk layout method for object-based storage devices is disclosed. A disk is initialized and a root object is added while a set of blocks of the disk are configured to store attributes of the root object, a free block index table, and a partition object index table. When a partition object is added, a set of blocks of the disk are configured to store attributes of the partition object, a collection object index table, and a user object index table, wherein the partition object indexes the location of a collection object according to the collection object index table and the location of a user object according to the user object index table. When a collection or user object is added, necessary blocks of the disk are configured to store individual data.