Abstract: For accelerator driven sub-critical system (ADS) injector Ⅱ, we designed the data archiving system which is used to gather devices state information and the order given from the central control room at run-time. The system can provide accurate reference information for trouble shooting and data analysis by accelerator maintenance personnel. It is based on Ethernet and running with the EPICS(Experimental Physics and Industrial Control System) environment. It uses channel access protocol (CA) to exchange data with devices. It uses keepalived software to achieve high available MySQL database services, uses the ArchiveEngine of CSS (Control System Studio)as data acquisition tool to store data in the database, and uses the DataBrower plugin in CSS for data query and curve plot. We optimized the archiving database for data query, and developed a run-time monitor program for database server and archive engine by ourselves to make the system more stable. The practical operation proves that the system can meet the user requirement of the ADS injector Ⅱ. The system has the feature of convenient maintenance, to gather the devices data we just need to add the corresponding PV (Process Variable) information into the channel table of the database.