Abstract: Some Background-substracted Methods to Improve the Degree of Match in Library SearchWang Conghui; Dong Fengxia(Institute of Forensic Science, Beijing 100038, China)Abstract:Library search of MS has been an effective shortcut to assign the chromatographicpeak,so how to get a high degree of match found between the unknowns and the reference spectra is a key in the processing of MS data. In this paper five experimental skillsfor background-substracted method are recommended and some specific examples are also illustrated.Keywords: background-substracted method, degree of match, library search.