Abstract: The present invention relates to automatic document classification system and method by which categories for fields is learned in a genetic learning classifier for performing a learning process using a genetic algorithm, and documents are classified into respective field categories by inputting term clusters for a keyword of the documents in the genetic learning classifier, and a system for allowing a user to store a search word used in the search in a user profile and to input the keyword to the genetic learning classifier to determine an interested field of the user. The present invention can be utilized in an automatic classification of the document in a directory service used in the wet search system. Therefore, the present invention can improve the search efficiency by utilizing an interested field of the user when the user searches the search result later.