The invention provides a global data encryption system aiming at disks. The global data encryption system comprises an encryption algorithm configuration module, an initialization module and a data encryption and decryption module. The encryption algorithm configuration module is used for setting a global data encryption algorithm for a disk; the initialization module is used for encrypting disk starting information in dependence on the set global encryption algorithm; and the data encryption and decryption module is used for encrypting and decrypting sector data of the disk in dependence on the set global encryption algorithm. The encryption algorithm configuration module further comprises a global encryption configuration file, an encryption function library and a user configuration interface. The encryption function library is used for storing several encryption algorithms; the user configuration interface is used for selecting the encryption algorithms in the encryption function library; and the encryption configuration module is used for recording the selected encryption algorithm to the global encryption configuration file. According to the invention, the disk is packaged in detail and is hidden to be a unified data object, through encryption and decryption of the data object, efficient encryption and decryption operations of the disk are achieved.