Abstract: The scientific evaluation of urban green space provides data support for green space planning, and plays an important role in building sustainable and healthy city. This paper develops an indicator system for evaluating the urban green space under the new data environment, from the perspectives of shape, quality, vitality and services. Based on the theory of “Big Model”, it carries out multi-scale assessments of the green space in downtown areas of 287 Chinese cities, and takes Zunyi as a case study for evaluating the quality and vitality of urban green space. To make the research more objective, unified and comparable, it solves key issues including the extraction of spatial data of urban green space, and the definition of downtowns. The results show that at the scale of green patch, the overall compactness of urban green space is high, and most green spaces are located near the city center. At the urban scale, the average service level of urban green space of 287 Chinese cities is 57.45%, while the sub-provincial cities have higher average service level, and the prefecture-level cities have the lowest service level. This paper analyzes the shortages and problems of the regional urban green space to provide reference for the construction of urban green space in the future.