Based on the cloud-to-ground(CG) lightning data of Jiangsu from 2006 to 2009, a study was made of the general characteristics, lightning intensity and temporal-spatial distribution of CG lightning in Jiangsu. According to the thunderstorm days in 13 cities of Jiangsu, equations for calculating density of ground lightning are given. It shows that most of CG flashes are negative, the mean intensity of positive CG flashes are bigger than the negative ones, the CG lightning varies a lot daily and monthly, meanwhile the spatial distribution differs from place to place, we should pay more attention to some dense areas. The structures which are protected by lightning rods still have probabilities to be damaged by lightning. 9775% of lightning in Jiangsu is below 100 kA. The calculation result based on local density of ground lightning is more accurate than that calculated by IEC formula.