The monitoring data of Jiangsu Provincial Lightning Positioning System from 2006 to 2009 are used to analyze the characteristics of lightning activity in Nanjing.It is found that,most of the lightning happens at 12-20 P.M.in June-August and few happens in other months,because the convective activities frequently happen in summer in Nanjing and in the period of the midday to sunset,due to the always high temperature,which is easy to produce strong convective thunderstorm;The average density of lightning striking the earth is between 2-6 times/(km²·a) in most Nanjing area,and the maximum center is in Jiangning district.The average lightning strike intensity is between 5-40 kA,and the maximum center is near Nanjing Yangtze River Bridge,where the intensity is 75 kA or more.Topography,land surface properties,moisture conditions and other factors may be the main reason leading to the above characteristics.The lightning activity characteristics and lightning parameters obtained in this study are valuable in the lightning protection,lightning risk assessment and other areas.