Abstract: The phenomenon of urban heat island has attracted people’s attention widely, especially in mega cities, while little attention has paid to small and mediumsized cities. The area and spatial pattern of various landuse types have different impacts on urban island, but we have little knowledge about the quantitative relationship between them, and small cities usually have different landuse patterns from mega cities. Changshu City close to Shanghai was taken as a representative small city in our study to analyze the relationship between urban heat island and various landuse types by using landscape ecology approach. The timeseries HJ satellite images in 2013 were employed to map land use of Changshu, and multitemporal Landsat8 OLI images were used to inverse the seasonal surface temperature. The results indicated that the intensity of heat island of Changshu was the strongest in winter due to the “warm island” effect of paddy field and dryland, while the weakest in summer due to water body’s “cold island” effect. Therefore, Changshu had a relatively favorable surface thermal environment. Meanwhile, the results also showed that there existed a threshold, beyond which the influence of waters, wetlands, forests on the urban heat island was no longer significant. We analyzed the impact factors of the construction land surface temperature by using GeogDetector approach. The results showed that water body had the greatest impact on construction land surface temperature in summer, while dryland had the greatest impact in winter. Our results provide suggestions for urban planning to maintain a better ecoenvironment in Changshu.