This study analyzes the recognition of commercial business men and employers who operate the commercial zone along the streets in the downtown area on the planting for the roadside green space forming the important frame of greening in the downtown among the open spaces. Through the analysis, this study attempts to get the basic data to suggest the recommendable directions in planting and managing the street trees in the downtown. The results of this study are summarized as described below. The street green spaces are very important in improving the environment of the downtown and their necessities are also very critical. It was found that the street trees were recognized as the critical factor to enhance the aesthetical values of the city, provide the green shades and purify the air. This study also identified that the street trees have the positive impacts on the business environment rather than negative impacts. In maintaining the street green spaces, the most necessity is the service facility such as resting areas, toilets and garbage bins with the street trees. The commercial business men and employers who operate the businesses along the streets preferred the double layer type that the tall trees and green walls are planted together along the streets for the street planting. For securing the green shades in the city, the planting of linear green spaces such as streets and waterways is critical. Moreover, the street trees accounts for the important position in the urban open spaces. The majority of commercial business men and employers consider the participation of citizens for greening as the very essential factor.