The purpose of this study was to estimate the carbon dioxide absorptions in the city park by analyzing facilities carbon emissions and absorption of trees. Eco-friendly plan of city park is presented for energy conservation. $CO_2$ emissions are estimated by usages of electricity and water utility in currently under operation. $CO_2$ absorptions are estimated by Equations based on a variety of trees. The results of this study were as follows; $CO_2$ emissions of the parks was less than $CO_2$ absorptions by 10%. Absorptions can be secured by application of high-efficiency equipment and renewable energy. Ideal application of renewable energy can be estimated by the simulation of various target site. And further studies on the LCC of the park will be needed.