The building sector is critical to achieving China’s energy conservation and emission reduction targets because it has contributed to more than 30% of the national energy consumption in the past decades. Green building construction has become a nationwide trend with the aim of energy conservation. The science research building of China State Construction Technical Center (CSCTC) has been labeled as the benchmark for energy conservation. Rendering the first-hand data, this study employs an ecological input-output model to analyze its life cycle energy and environmental performance. It further introduces scenario analysis and sensitivity analysis to study the critical factors that affect its energy consumption over its 50-year lifespan. This study has reached several conclusions. First, embodied energy and emissions dominate the life cycle energy and greenhouse gas (GHG) emissions in a green building. Whilst higher replacement frequency dominates increasing energy consumption, it is indispensable to maintain the well-being of research buildings. Second, installing a rooftop solar photovoltaic system could triple the effect of reducing emissions than that of changing power mix. Moreover, it is imperative to take the functional and safety requirements of research buildings into account when formulating policies.