[Objective] The impacts of landscape pattern on urban thermal environment were studied to support the strategies that can mitigate extreme thermal environment caused by rapid urbanization in living environments and industrial production.[Methods] Based on Landsat images in 1996, 2008 and 2017 in Zhangjiakou City of Hebei Province, land surface temperature (LST) retrieval was conducted to quantify and map the thermal environment. Meanwhile, the landscape pattern index was obtained by moving window method at a grid scale. Finally, the specific relationship between the landscape pattern and LST was analyzed quantitatively and spatially.[Results] ① The changes of landscape pattern were featured by the expansion of impervious surface landscape with an increase of more than 81.26 km² from 1996 to 2017, followed by the reduction in vegetation landscape (61.78 km²). ② During the study period, the average LST of the study area increased by approximately 3℃, and the impervious surface landscape and vegetation landscape as the "heat source" landscape and the "cold source" landscape maintained the average LST of 27.29℃ and 23.77℃, respectively. ③ For every 10% decrease in the proportion of vegetation landscape and water landscape area, the corresponding LST decreased by 2.71℃ and 5.77℃, respectively. For every 10% increase in the proportion of impervious surface area, LST increased by 0.25℃. Landscape aggregation, shape index and proportion of cultivated area all maintained a non-linear correlation with LST.[Conclusion] The urban's thermal environment has developed towards a high level in Zhangjiakou City in the last two decades, which was strongly related to both the increase in impervious surface and reduction in vegetation.