Cities all over the world have been warming up in the summer over the years. Seoul, Korea, is also an example of how a city was transformed into an urban heat island. Green areas produce social, economical and environmental benefits in highly populated urban areas. This study is to investigate the micro-climate changes and urban-scale cooling load reduction by the recently restored Cheonggye stream, also known as Cheonggyecheon, in Seoul, Korea. Under the urban development in 1950’s, Cheonggye stream located in central Seoul had been covered with pavement and the overpass of concrete structures for 58 years. A lot of surrounding buildings, traffic and people caused Cheonggye stream area to be getting hotter than other districts. For the urban environmental renovation, 5.84km-long stream was restored on September 2004. Since the restoration, the ecosystem in the center of Seoul is reviving. This simulation study analyzes the micro-climate changes in restored Cheonggye stream and its surroundings by using Envi-Met, a microclimate model designed to simulate the surface-plant-air interactions in urban environment. We employed TRNSYS to estimate the urban scaled cooling load reduction by means of the output data of Envi-Met simulation. The results indicated the cooling benefits of the restored stream areas are promising at the surrounding built environments.