Abstract: Social network is a relatively stable relation system formed by the interaction among social individuals. It pays attention to the interactions and relations among peoples. The social interactions can influence peoples social behaviors. Extenics is a new discipline founded by Chinese. Its logical cell is basicelement. Through the formalized research for affair, matter and relation, the informationknowledgestrategy formalized system, extension analysis methods, conjugate analysis methods, extension transformation methods and superiority evaluation method are set up. We explore strategies generating methods to solve contradictory problems by taking extension set and dependent function as quantificational tools. This article applies extension theory and extension innovation methods to the research of social network structure. Firstly, we structure a basicelement net for social network, then analyze society and evaluate social network by using basicelements analysis, transformations and evaluating methods. Therefore we can recognize social network from the angle of combining qualitative analysis with quantitative analysis. It can provide a new and operable method for putting up social structure research with computer and network technology, and accordingly establish a social structure research method.

Key words: extenics; social network; basicelement; extension innovation method; social structure