The green and sustainable construction has become a popular topic, especially with the respect of the green house gas emissions. Meanwhile, the estimation of the CO2 emission during the construction is an important process among the CO2 emission management. The paper carries out the empirical research on the construction CO2 emission based on the EPA non-road modeling and a real case. Firstly, the research methodology is developed based on the EPA non-road modeling. Then, based on a real case, the total CO2 emission of the project and the CO2 emission of each machine are calculated. Finally, other scenarios are considered and compared, and the optimal solution is found. The proposed methodology provides an accurate, consistent & realistic quantification method of CO2 emissions at micro level during construction, which will be of benefit to the green and sustainable construction.