The urban heat island (UHI) phenomenon is not only a common environmental problem in urban landscapes which affects both climatic and ecological processes, but also one of hot climatic research topics in urban area. Tanshan city, located in the northern-east of Hebei province, has been undergoing faster economic growth and urbanization compared with other cities in the region. To combat UHI for the city and provide soundable eco-city development planning, we retrieved the brightness temperature and relative brightness temperature from Landsat TM thermal-infrared datasets over the city obtained on August 18, 1993 and August 30, 2009, respectively. The spatial and dynamics of heat field over the administrative region of the city and sub-regions were analyzed in this paper. The result showed that the surface heat temperature was higher in the eastern and central part of Tangshan than that in other parts of the city. The most prominent heat island was mainly observed in the Coastal Low-plain Wetland Conservation Sub-region, Caofeidian Recycling Economy and New Urban Development Sub-region, and Middle Urban and Village Construction Sub-region. The area of green island and severe heat island, in terms of relative brightness temperature, has been increased very fast, reaching 38326.05ha and 25497.81ha respectively from 1993 to 2009. In addition, the area of very severe heat island was 3.88 times larger in 2009 than that in 1993. The green open space, one of the most stable thermo patches, has been unchanged by a percent of 77.6% from 1993 to 2009. However, the area of very serve heat island unchanged was only 2.95% while the areas of other relative heat temperature classes unchanged under 50%. We also found that the green island patches interpreted from TM image in 2009 were contributed by 73.81%from green islands and 23.11% from slight heat islands. The slight heat island was contributed by 33.72% from green island and 16.11% from moderate heat island. The moderate heat island was contributed by 18.25% from green islands and 39.33% from slight heat islands. For severe heat island, there was only 12.5% of the area in 2009 is from the same type. As for very severe heat island, almost 99% of area in 2009 was newly produced by 39.4% from green island and 36.35% from slight heat island. We finally discussed the reasons of the surface heat temperature from NDVI, land use/land cover changes, urban built-in structures, agriculture development, and industry booming.