Population growth and urban development are of the effective factors of increasing air temperature in urban areas that may cause formation of heat island which itself influences air quality and as a result, public health. In this research TM images of LANDSAT 5 in 25 Jun 1992 and ETM+ of LANDSAT 7 in 6 Aug 2002 were investigated to study urban heat island in Mashhad city and temperature and Land-use maps were obtained by using them. Also for better investigation of this phenomenon, were considered the profiles in that direction North-South, East-west and Northwest-Southeast. Moreover, the fractal dimensions of these profiles were computed by using the box counting method to have better understanding of thermal behavior of different coverings and the effects of land-space pattern on ambient temperature. The results showed that the surface radiant temperature of Mashhad during the decade 1992 to 2002 has increased generally and this increase is more remarkable in residential areas. Land-use maps show the development of residential areas in 2002 than 1992 and many plant covers have been destroyed and this was also approved by calculated fractal dimensions. The results also showed that the profile of Northwest – Southeast has higher fractal dimensions compared to other profiles, due to the more furtherance of the city and lack of surfaces uniformity.

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