Abstract: Query efficiency is an important indicator of database systems,but query optimization is a difficult  research focus.This paper presents a query based on genetic algorithm optimization method.The method uses keyword preprocessing module,which transforms keyword  that users enter into the internal keywords to improve query accuracy.In order to speed up query response time,statistical record index table of researches is established.In case of  repeated searches,full database scan can be avoided.When full database scan is recessary,the use of genetic algorithm,the optimal solution is proposed.Correlation calculation method is used,which is operated according to the degree of relevancy of queries.

Key words: keyword matching, index table, genetic algorithm, relevancy