Abstract: The composition and structure of urban landscape and human activity intensity are key factors shaping urban thermal fields, whereas the relative importance of influencing factors for urban thermal distribution remains unclear. We carried out a case study in Yixing City. Land surface temperature (LST), ecological infrastructure (including vegetation and water cover), building volume and point of interest data were extracted from the RS interpretation, field mapping and programming technique. Using Pearson correlation analysis, univariete regression analysis, multiple regression analysis and relative weight analysis, we quantitatively analyzed the relationships between urban land surface temperature to ecological infrastructure, building volume, POI density at multiple scales (500, 1000, 2000 m) as well as their relative importance. The results showed that ecological infrastructure had a significant cooling effect, and the building volume and POI density were positively correlated with LST. Among the influence factors of urban heat field, ecological infrastructure had the highest relative weight (21.3%-43.8%), followed by building volume (20.7%-22.6%) and POI density (13.7%-21.7%). Our results would help to understand the relative importance of factors driving urban thermal field and offer important reference for taking mitigation measures to alleviate urban heat island effect.