Abstract: Users often have fuzzy or imprecise requests when querying XML documents.Based on algebraic operations， a novel approach was proposed to express user’s fuzzy query intention.A set of fuzzy algebraic operations was defined， which could support fuzzy query in XML.The user’s fuzzy query condition was respected by the fuzzy query results perfectly.To deal with the problem of too many query results， a ranking approach was proposed， which considered the relevance between the membership degree and user-defined weights.The top-k answers of the fuzzy query results were computed efficiently.The efficiency of the method was demonstrated by the results of a preliminary user study.The user’s fuzzy query intention could be captured by fuzzy algebraic operations effectively.

Key words: XML, fuzzy algebraic operations, fuzzy query, ranking, fuzzy set