Abstract: In the practical application，there often exists uncertainty and ambiguity in the data. Keyword query processing over fuzzy XML data becomes a requirement for non professional users. Aiming at making a research on the method of keyword querying over fuzzy XML data，the semantics of keyword querying over fuzzy XML was analyzed， and a new coding method CDewey for the fuzzy XML document was proposed. Types of nodes could be effectively distinguished by this coding method. On the bases， a keyword query algorithm FIndex Loop was proposed， this algorithm can get the SLCA results of keywords inputted and values of possibilities of the results accurately. Finally， experimental results showed the effectiveness of the query method.

Key words: fuzzy XML, keyword, index, query, possibility