This article aims at studying co-author network of library and information science according to all the authors in the field of library and information science during 1999-2008. Using traditional expert survey method to identify 20 authorities, it is found that the 20 authorities have significant difference in the four indices: vertex value, point centrality, betweenness centrality, closeness centrality, compared to the random 1000 authors’. Take the 20 authorities’ index value as a benchmark to seek the other 17 eligible authors, we conducted a questionnaire survey to weight their authority. It is concluded that social network analysis method is feasible and effective to determine academic talents.