Under the background of global warming, the urban heat wave in summer has become one of the most serious meteorological disasters, which has brought tremendous impact on the health and economic development of urban residents. Taking the heat wave disaster event occurred in Nanjing from August 7 to 13, 2013 as an example, the near- surface air temperatures were estimated based on the downscaled MODIS land surface temperature using the Landsat 8 OLI image data, MODIS data products, and field-measurement meteorological data. Combined with the spatial interpolation data of the relative humidity, the hot index and the high temperature heat- wave index at the resolution of 100m were calculated, and then their spatial and temporal distribution characteristics were analyzed. The results show that during the evolution of the high temperature heat wave in Nanjing, the hot index increased firstly and then decreased with time. The hot index was highest on Aug. 11th with an average of 86.99, and it fell off to the lowest value of 85.05 on Aug. 12th; the heat wave intensity mainly concentrates on mild and moderate degrees, and its range also shows a tendency of expanding firstly and then decreasing with time. In terms of spatial distribution, the hot index is higher in northern region and central urban areas and mainly display as a moderate heat wave, while the heat index in the southern suburbs and central suburbs is lower and the heat wave is mild, and the mountain and the water areas have the lowest heat index.