Based on the analysis of the development of welding technology and characteristics of welding discipline,this paper points out that in the field of patent examination,books retrieval has an important meaning,and Duxiu Knowledge Search Database shows as one of the most important database,and is the necessary searching database in welding field,and combined with case analysis elaborated to point out Duxiu Knowledge Search Database is of importance in acquiring closest prior art,proofing common general knowledge,auxiliary reasoning,understanding and responding to comments stated by the applicant.