From the strategic consideration of sustainable development, it is the general trend to develop new building systems in the 21st century to select ecological environment building materials that consume as little resources as possible, have little impact on the ecological environment, and have high recycling rates. Relying on the life cycle evaluation (LCA) theory, the total life cycle of carbon accounting model is established in this paper. Moreover, to explore methods of reducing carbon emissions in buildings and the selection of suitable structure types and structural materials, this paper focuses on two different structure types: heavy structure (steel structure, reinforced concrete structure) and light structure (wood structure, light steel structure). Starting with the corresponding structural materials, quantitative measurement and comparative analysis of the whole life cycle’s carbon emissions are carried out. The results of the research show that in terms of carbon emissions per unit building area per year, light structure < heavy structure; wood structure < light steel structure < steel structure < reinforced concrete structure.