Abstract: Through collecting the measured data, including the atmospheric temperatures of recent 50 years and the ground temperatures at different depths of recent 30 years at an observation station in Nanjing city, the relationship of the ground temperatures with the atmospheric temperatures and the changing trend of ground temperatures are analyzed. The variations of ground temperatures, variation of daily mean ground temperatures and daily ranges of ground temperatures are also studied. The results show that, the ground temperature changes have a good correlation with the atmospheric temperatures, however, with a lag.The change regularity of monthly mean ground temperatures of Nanjing city is basically similar, and the maximum values occur in July or August, and the minimum in January or February each year. In general, the ground temperatures increase gradually during the recent 30 years, with the maximum increment on the ground surface of 2.8 ℃， at the 20 cm depth of 2.0 ℃ and at the 40 cm depth of 1.75 ℃. The greatest temperature difference on the surface reaches 84.5 ℃, and at the 40 cm depth reaches 27.5 ℃.Therefore, some possible influence due to ground temperature rising on the engineering geological properties of superficial soil layers inside the Nanjing city area can not be ignored.