Journal of Digital Information Management WEN Fang-Fang 14 1 2016 http://dline.info/fpaper/jdim/v14i1/v14i1_4.pdf This paper describes a quantitative study on interdisciplinary technological relatedness represented by patent co-classification. Taking patents in the electricity sector as samples, classification analysis was conducted on the basis of 4-digit codes of International Patent Classification. Then, social network analysis and visualization technique were conducted. The relatedness between different subclasses was measured and visualized. The focus and trend were detected. The results indicate that "H04L: Transmission of digital information" is the most active subclass that can be considered as the focus in the field of electricity. It also suggests that hot domains characterized by high interdisciplinarity may involve some emerging technologies, driven by knowledge relatedness and characterized by technological diversification. The results obtained in this study are expected to provide an improved understanding of technological development and evolving characteristics, as well as provide insights that can contribute to further research and development.