Kunshan is located in the Yangtze River Delta Megalopolis, and its significantly affected by Shanghai, Suzhou and other large and medium-sized cities in terms of urban heat island(UHI). Based on the analysis of the spatial and temporal distribution characteristics of urban heat island intensity (UHII) in Kunshan by using the hourly observation data of Kunshan meteorological stations from 2014 to 2017,combined with Normalized Butding Index(NDBI), this study investigated the impact of urban functional division and urban expansion on the UHII. A set of the systematic site classification method for urban climate research,namely the Local Climate Zone system (LCZ), was also applied to investigate the characteristics of UHII of different urban landuses in Kunshan. The results were shown as follows:The UHII was generally strong at night but weak during the day in Kunshan. In terms of seasonal variation, the average UHII was the strongest in autumn, followed by winter, and relatively weaker in spring and summer. The UHII has been increasing year by year in Kunshan and the highest annual UHII growth rate among the towns was 0.19℃·a^-1. The range of high UHII extended from southeast to northwest. The lake-land breeze had a certain influence on the distribution and variation of diurnal UHII. Due to the role of water bodies, the correlation between the NDBI and the nighttime UHII was weak, but NDBI was highly positively correlated with the daytime UHII. The different functional division of each town in Kunshan had significant impact on the UHI, and when the average NDBI of each town increased by 0.1, the average daytime UHII would increase by 0.16℃. It was found that the heat island intensity (HII) of different LCZs was significantly different, and the higher the urbanization degree of the land, the stronger the heat island (HI) effect. The HII of compact low-rise zones (LCZ 3) and heavy industry zones (LCZ 10) was closely related to the human activities. The HII in the open low-rise zones (LCZ 6) and the dense trees zones (LCZ A) showed similar characteristics of variation. The forest green space (LCZ A, LCZ B) had a mitigating effect on the HI. The water body (LCZ G) had a certain cooling effect during the day, but it can aggravated the HI at night.