The invention discloses a method and a device for protecting storage medium. The method for protecting storage medium is applied to storage equipment comprising a plurality of different storage media and comprises the following steps: unifying the structure of the storage medium and management of information; dividing logic blocks for conveniently searching a physical block with the least erasingtimes; and providing the physical block with the least erasing times to store data. The method and the device for protecting storage medium achieve the purpose of protecting the storage medium in thedevice through providing the physical block which accords with the requirement and has the least erasing times for data storage.