The essentiality of disaster recovery for consecutive operation w as introduced .Several methods of disaster recovery , main principles and design schemes were given.Through analyzing the logic structure of short message platform of personal access phone system (PHS), functional request for disaster recovery system was put forward.According to functional request for disaster recovery system , the logic structure of disaster recovery system was determined.The test data package w as designed to verify whether is the system malfunctions.To test the data changes of different members in data package decided net situation among cur rent functional modules and between functional modules and monitor modules , and work situation of all function modules.The data change rules to arise breakdown were given .In terms of rules , switch condition between the main module and the backup module was set .While a breakdown that the system can get rid of automatically appears , the system provides a sound alarm and the breakdown is eliminated automatically .When a breakdown that the system cannot fix appears, the system informs the administrator by a shor t message or E-mail to restart the system