The information resources on network is increasing rapidly. How to org anize these resources better becomes more important. On the foundation of analyz ing and evaluating two existing index methods of search engine-keyword index an d hierarchical subject index, this paper puts forward one new method-united ind ex, which unites the two forenamed indexes completely, exerts sufficiently stron gpoint of them. Its central thought is : on the foundation of 《China Classifica tion-Subject Corresponding Table》,handpick subjects, and build subject trees according their discipline hierarchical relations; then link keywords extracted by automatic index softw are to corresponding subject according their semitic relat ions. The united index would automate enrich work of hierarchical subject index and make advanced intelligence search of keywords come true.