目前城市植被降温效率的研究大多基于大尺度卫星遥感数据来开展，缺少微尺度下植被降温效率的精细研究。因此，本研究以南京市江宁区典型居民区植被为研究对象，利用无人机可见光数据进行居民区绿地精细分类，在此基础上建立区域绿地容积率(Regional Green Plot Ratio, RGPR)指标，基于逐小时无人机热红外数据，提出一种改进的植被降温效率计算方法—区域植被降温效率(Regional Cooling Efficiency, RCE)计算方法，并利用该方法计算居民区植被降温效率，探究不同局地气候分区(LCZ)下居民区地表温度与区域绿地容积率指标的响应关系、降温效率时空变化并进一步确定不同居民区绿地容积率的最佳降温效率阈值。研究结果表明：（1）居民区植被降温效率日变化曲线整体呈现“山峰”形态， RCE随地表温度增强而增大。在观测时间段内，RCE最小值出现在8:00（均低于1.0℃），最大值出现在午后14:00（均大于1.4℃），局地气候分区水平下，紧凑型居民区的RCE高于开阔型居民区，而在开阔型居民区类型中，RCE随着区域内建筑平均高度的增加而降低。（2）紧凑型的局地气候分区下，RGPR越高，植被所带来降温效果越强；而开阔型居民区，无论建筑高低，植被降温效率存在一定的RGPR阈值，当RGPR达到一定阈值后，RGPR对地表温度的降温效率达到最大强度。本研究将助力于城市居民区绿地规划，为改善城市微热环境提供科学的理论支撑。

Objective : Most of previous studies on the cooling efficiency of urban vegetation are based on the large-scale of satellite remote sensing data, leaving a gap in fine-scale investigations at the micro-level. Therefore, this paper took the vegetation of typical residential areas in Jiangning District of Nanjing City as the research object, UAV visible light data was used to obtain the fine classification of residential green space, and the Regional Green Plot Ratio (RGPR) index was constructed. Method : And then We proposed an improved calculating method of vegetation cooling efficiency—Regional Cooling Efficiency (RCE) based on hour-by-hour UAV thermal infrared data. We applied this method to calculate the cooling efficiency of vegetation in residential areas, investigating the response relationship between the surface tem-perature of different local climate zones (LCZs) residential areas and the RGPR indicator and further determining the optimal thresholds of cooling efficiency for different RGPRs in residential areas. Result :The results showed that: (1) the daily variation curve of the cooling efficiency of vegetation in the resi-dential area shows a "peak" pattern, and the RCE increases with the increase of solar radiation. During the observation period, the minimum value of RCE appeared at 8:00 a.m. (all lower than 1.0℃), and the maximum value appeared at 14:00 p.m. (all higher than 1.4℃). At the level of local climate zone, the RCE of compact residential areas was higher than that of open residential areas, and in the case of open residential areas, the RCE decreased with the increase of the average height of the buildings in the area. (2) Under compact local climate zone, the higher the RGPR, the stronger the cooling effect brought by vegetation, while in open residential areas, regardless of the height of the building, there is a certain RGPR threshold for the cooling efficiency of vegetation, and when the RGPR reaches a certain threshold, the cooling efficiency of the RGPR on surface temperatures reaches its maximum intensity. Conclusion : Overall, this study proposes a method for calculating the cooling efficiency of vegetation in resi-dential areas at the micro-scale for high-resolution unmanned aerial vehicle (UAV) data, and investigates the cooling efficiency of vegetation and the optimal cooling efficiency thresholds for different types of residential areas at the level of localized climate zones. This study can help to improve the urban thermal environment and provide more specific and scientific theoretical guidance and support for enhancing urban sustainability.