以长三角城市群为研究区，基于时序多源遥感数据，通过均值标准差法对城市热岛等级进行分类，研究长三角城市群城市热岛时空分异特征，同时从下垫面属性、人为活动和植被覆盖等角度探索其城市热岛形成机制，可为缓解城市热岛效应提供一定参考。研究结果表明，长三角城市群2013—2018年城市热岛现象明显且呈增强趋势，其城市热岛空间分布呈现“M”型空间分布，具有较强的时空分异；浙江省和江苏省大部分城市的城市热岛较强，而安徽省大部分城市的城市热岛分布范围较小。长三角城市群的城市热岛与建成区空间分布表现出一致性，其热岛效应的增强与建成区和郊区林地面积的增长有关；长三角城市群的城市热岛与夜间灯光分布和植被覆盖空间分布均呈现空间一致性，城市热岛与夜间灯光强度成正比关系，与植被覆盖呈反比关系。

Based on multi-source remote sensing data in time series, we classified urban heat island(UHI) classes by means of standard deviation method, and studied the spatio-temporal characteristics of UHI in the Yangtze River Delta(YRD). Then, we explored the formation mechanism of UHI from the perspectives of underlying surface properties, human activities and vegetation coverage. The results showed that UHI phenomenon in YRD was obvious and showed an increasing trend from 2013 to 2018. The spatial distribution of UHI in the form of “M” and showed strong spatio-temporal differentiation. The UHI of most cities in Zhejiang Province and Jiangsu Province were strong, while the UHI of Anhui Province was small for most of the cities. The spatial distribution of UHI in YRD was consistent with that of the built-up area, and the enhancement of UHI effect was related to the increase of built-up area and suburban forest area. The UHI of YRD was in spatial consistency with the distribution of nighttime light and the spatial distribution of vegetation coverage. The UHI of YRD was positively related to the intensity of nighttime light and negatively related to the vegetation coverage. This study explored the formation mechanism of UHI, which could provide some references for alleviating UHI effect.