This research aims to predict and analyze green building certification market of Korean Peninsula after unification. First, it analyzes prospected unification time period, then it forecasts number of new residential and non-residential buildings to be constructed based on estimated number of residences in short at the time in North Korea. There exists a good chance that North Korea's new building market forms similar to that of South Korea, as unification would thoroughly proceed which would result levels of economic culture social politics in quasi-equal state. Thus, assuming the ratio of residential and non-residential building against population is similar in both Korea's, the number against North Korea's house supplied population can be estimated. Based on the expected numbers in North Korea, number of proceeded Building Energy Conservation Plan, Building Energy Rating Certification, and Green Standard for Energy and Environmental Design (G-SEED) are predicted. The research shows certification market related to green building in united Korean Peninsula to be \660 billion over 10 years. Not only certifications to newly built buildings but also including existing buildings, this market is to grow to a considerable extent. As this would largely influence eco-constructive materials, energy plant/equipment, and other relevant markets as well, it would require to make thorough preparations. In sum, to stabilize green building market even before the unification, the research proposes the necessities of appropriate systems in consideration of North Korea, through in-depth discussions and establishment of technology and policy directions in green building sector, such as building energy management and emission reduction technology.