As the development of advertising industry and media the research about an advertisement get accomplished. As the result information resources called on the advertising materials are on an Increasing trend. However, it looks into the classification system In advertising field of KDC, the problems are as the follows : (1) the classification items are too incomplete, (2) the main class is badly arranged. The reason have no regard for the correlation with a science. So, it gives rise to confusion to the librarian and user. The purpose of the study is to present the improvement plan on the classification system in advertising field of KDC. In order to build the improvement plan, the four steps are utilized. The first step Is to investigate the characteristic of sciences on advertising and a type. The second one is to survey the current status of the library classification as KDC, NDC, DDC, and LCC. The third one is to analyse the classification system of library and web site on the advertising. The forth one is to grasp the problems on the classification system In advertising field of KDC.