A computer aided indexing system for CCDOC (Chinese Chemical Docum ent) database is introduced in this paper. The system is designed to improve the effi ciency to set up the database and the quality of the database. It works under Microsoft Wi ndows (version 3.1), therefore it is portable and has a friendly interface. As an intr oduction, this paper focuses on functions of the system, the benefits it brings to the on going work of post control indexing. Finally the further development of the system is discussed.