This chapter employs social network analysis methods to systematically examine the spatial correlation network characteristics of carbon emission intensity between OECD countries and China from 1995 to 2022. The results indicate that network density has continued to rise, reflecting enhanced regional collaboration; however, network efficiency has declined, suggesting an increased risk of information redundancy, which may weaken the effectiveness of policy diffusion. Core countries such as Germany, the USA, and China occupy central positions in the network, while smaller countries tend to be marginalized. Role evolution indicates that the functional positioning of countries is dynamically adjusted. Based on this, this chapter proposes policy recommendations to strengthen transnational cooperation platforms, focusing on key node countries, supporting peripheral and proxy countries, and optimizing the network structure. The study calls for the inclusion of more emerging economies in the future and further exploration of policy implementation mechanisms and their network impacts.