Under the background of the socio-economic transition in China, the quality of urban life space has been strongly focused by residents, scholars and the government. The paper uses multi-source data to expand the evaluation dimension and method of urban living space quality and constructs the evaluation index system from five dimensions: comfort, convenience, health, safety, and sociality. Taking Nanjing as an example, the paper evaluates the living space quality by GIS spatial analysis to find the distribution law of urban living space quality in Nanjing. The empirical analysis shows that: 1)There is obvious spatial differentiation in the urban living space quality of Nanjing. The high-quality living space presents an obvious hierarchical agglomeration feature. The main center is located in the circle of 1-3km around the core area, and the overall distribution of low-quality living space is more dispersed. 2)Among the five dimensions that constitute the quality of living space, the quality of comfort and sociality is increasing from the center to the periphery. The quality of convenience is declining from the center to the periphery. The quality of health is declining from the northwest to the southeast. The high value of safety is not significant and the low value is concentrated in the city center. Based on the analysis, the optimization measures were proposed for planning practice.