The control system of HLS (Hefei Light Source) is based on EPICS. The control data is held in a distributed database, which resides in several IOCs. An EPICS tool, AR, is used to archive the control data. A data management system is developed to manage the archived data. A number of CGI programs make it easy to access the data via WWW, and the programs also provide several functions for analyzing the data. The results can be displayed in various modes.