According to the greenhouse reduction scheme of the government, construction sector targeted 7.1% reduction by 2020. Although this target is not higher than other industrial sectors, it is not easy to achieve the reduction target without radical advance in technology, which cannot be expected to happen soon, considering the conservative characteristics of construction industry. Although there have been not a few researches on greenhouse gas reduction, mostly of them focus on the issues related to energy saving matters during material production stage or maintenance stage, such as heating and insulation, and few deal with the issues directly related to the energy use in the construction site of buildings. Energy use and greenhouse gas emission in construction sites are mostly caused by equipments and machines for transportation and on-site assembly. This research regards the operation of equipments for transportation and on-site assembly of materials and related equipments as a system and provides a dynamic model adopting stock and flow concept which is frequently used in system dynamics modelling. The dynamic system model provided in this research can aid construction planners estimating the patterns of energy use and greenhouse gas emission as well as help selecting alternatives of plans.