The purpose of this study is to examine, through social network analysis, how the centrality of specific firms (nodes) changes when tie strength is incorporated into buyer-supplier transaction relationships (links) using actual transaction data in the automobile industry. To this end, the study was conducted on eight local joint ventures of global automakers operating in China (Shanghai Volkswagen, FAW-Volkswagen, Guangzhou Toyota, Guangzhou Honda, Shanghai GM, Changan Ford, Beijing Hyundai, and Dongfeng Yueda Kia) and their various suppliers. More specifically, for three product categories (airbags, interiors, and seats), transaction relationship networks and tie strength networks were compared to examine how degree centrality and eigenvector centrality change, and how network structures differ according to the characteristics of each product category. The results showed that when tie strength, a relational attribute, was added to the supply network, both degree centrality and eigenvector centrality values increased across all product categories. Furthermore, across all tie strength networks, it was confirmed that Korean automakers maintained relatively stronger ties with their own suppliers.