Abstract: This paper proposes a key-word query approach basing on relational database text field,aiming to search the expected result despite the wrongly input key words.The solution is to match the wrongly input key word and the"hot word "by setting up a" hot word database"to improve the dynamic programming algorithim in K-difference approximately string matching,so as to realize the relational database's error correction query.Experimental results show that this approach can achieve good retrieval performance.