A comprehensive introduction is made to the design and features of the atmospheric composition information platform for Dalian. Based on the database system, by independent modules to accomplish data entry, quality control and analytical processing, etc, the modularized system can deal with a variety of atmospheric composition data received by the meteorological department and generate various operational application products. The system is highly automatic and easy to use, upgrade, and extend, having great potential in application. Several solutions to the analysis, processing, and application of atmospheric composition data are given, which are useful for the atmospheric composition service.