Abstract: A new method which aims to determine the area of urban heat island (UHI) was proposed in this paper based on spatial statistical features by means of remote sensing and GIS spatial analysis tools, and was applied in the spatialtemporal evolution analysis of UHI in Hangzhou, China. The results showed that the area of UHI in Hangzhou increased 8.66 times from 1984 to 2010. During the 26 years, the spatial structure of UHI in Hangzhou had become more and more complex, and its spatial distribution changed from singlecenter to multicenter. Generally speaking, the change trend of thermal environment in Hangzhou was turning from lowtemperature spatial equilibrium to hightemperature spatial equilibrium. The major cause for the development of UHI in Hangzhou was urban expansion as it showed in the results of dynamic change detection. This  new method considered the spatial correlation of urban land surface temperature (LST), and reflected the global statistical features of LST. It was more objective and accurate than the conventional methods, and could provide more information, which would help us to resolve the problem of being lack of generality and comparability in the current research.