This study examines the Sino-Singapore Tianjin Eco-City (SSTEC) as a model of bilateral energy cooperation and sustainability governance between China and Singapore. Developed jointly by China and Singapore, SSTEC is promoted as a replicable template for sustainable urbanization. The research aims to evaluate how the project embodies both technical innovation and strategic environmental diplomacy, shaped by distinct national narratives. Three dimensions are explored: SSTEC’s historical and strategic foundations; the influence of China’s ecological civilization and Singapore’s technocratic eco-modernism on its discursive and institutional design; and its practical implementation, focusing on energy transition, citizen participation, and governance under China’s “Dual Carbon” strategy. Methodologically, it employs discourse analysis and policy document review. Findings reveal that global sustainability norms-such as low-carbon metrics and smart technologies-are selectively adapted within SSTEC to align with national priorities and local governance structures. Rather than a neutral urban model, SSTEC reflects a hybrid approach where global ideals intersect with post-authoritarian development logics.