Taking the streets of an old residential area in Chengdu, China, as an example, this study aims to analyse street as a transitional space that combines adjacent heterogeneous spaces.,The study framework of this paper consists of two parts. The first part focusses on the methods of landscape pattern analysis. The street spatial attributes are analysed, including the geometric and data characteristics of the city space. The second part involves a study of the stated preferences. The social attributes of space and the preferences of respondents regarding landscape properties are studied.,The study reports that the streets in the old residential area have characteristics of a fringe zone. The mechanisms of their edge effect improve the comprehensive quality of the urban space, stimulate a value-added effect and promote the overall development of the district economy.,The use of the spatial synergy of the edge effect can help us identify problems more accurately, enable streets to become suitable as public spaces, safeguard the rights of local residents to develop and eliminate the factors of instability.