In conventional chemical oxygen-iodine lasers (COIL),molecular iodine is injected directly into the main gas flow of singlet delta oxygen. Then ground state atomic iodine is obtained by the dissociation of molecular iodine with the consumption of energy of singlet delta oxygen molecules. This way of atomic iodine generation limits the small signal gain,output power,and chemical efficiency in the developments of COIL. In contrast,an alternative technique of injecting atomic iodine directly can not only avoid the above metioned drawbacks,but also broaden the application field of COIL. Recently,a great deal of efforts are devoted to new methods in which the ground state atomic iodine is produced by either discharge dissiciation or chemical reactions. The histroy of atomic iodine generation developments and recent research progress of atomic iodine generation by electrical discahrge methods and chemical methods are presented. The critical techniques of atomic iodine generation are summarized. The development trends are predicted and problems needed to be solved are pointed out.