Many countries over the world have taken many discussions and endeavors on environmental improvements of energy savings and greenhouse gas emission reductions for solving global climate change problems. In Korea, pre-considerations of environment-conscious factors in buildings have been taken to be critical with new constructions and renovation markets. In this situation, the Korean Green Building Certification(KGBC) system to induce the diffusion of sustainable buildings was introduced in 2002 and developed as an improved version of the G-SEED(Green Standard for Energy and Environmental Design) system in 2013 after major revisions. This research examines the importance of assessment criteria on apartment buildings to certify green buildings using the AHP(Analytic Hierarchy Process) method and suggests a new direction on certification assessment standards from the AHP result. In order to apply the AHP method, the survey via e-mail was conducted to design staffs in domestic architectural firms. As a result, assessment criteria such as ecological environment, indoor environment, and energy & environment pollution among 7 main ones proved to be important on assessing the G-SEED system for apartment buildings, while criteria such as land use & transportation, material & resource, water circulation management, maintenance management did relatively unimportant.