Because of the construction of the new building, global warming become more serious every day. So, the building-related greenhouse gas emission is the worthiest attention in the world. However, most policies are so independent without a perfect system. There would some problems in implementation of those policies. This essay explores the new methodology to identify difficulty and make China as a case study to prove that methods. Firstly, by using the LCA, we can define a responsibility model for the life-cycle GHG emissions of single buildings. By identifying the key stakeholders, such as investor, government and users, in the building's life cycle, we can find out the most responsible party for the GHG emission. Secondly, compare the cost for different stakeholders by the Cost - Benefit analysis methods to find out the reason for the barrier of policy implementation. Only in that way, we can identity the difficulties and provide the theoretical basis for the decision-maker in government. Finally, evaluate and analyze the greenhouse gas emission reduction policy in China and find out whether the existing emission reduction policy can handle the barriers above. Based on the conclusion of qualitative and quantitative analysis, the paper puts forward the advice and recommendations for greenhouse gas emission reduction in China.