By utilizing data of CG li ghnting from Lightning Monitoring Localization Network in Sichuan province and weather during the 2005-2008

a rather detailed study on characteristics of CG lightning over complex landform areas

which is in Sichuan province and its peripheral regions of China

has been carried out according to climatology analysis methods.Results show as follows.The distribution of CG lightning density correlates closely with the landform in research areas.The average annual density of total CG lightning increases from Western Sichuan Plateau to Sichuan Basin

and then to South hills in turn with the highest value over 1 000/grid

while the area with the highest one of positive CG lightning which is over 50/grid lies in Daocheng county of Ganzi state.The meridional highest frequency of total CG lightning is in the area with the latitude near 30°N in major thunderstorm seasons

and it is induced by subsidence flows of Hadley and Ferrel Cell at 30°N.Monthly percentages of positive CG lightning flashes in total ones for each year basically presents a "V" type.Two peak values of daily CG lightning frequency occur in east of the Western Sichuan Plateau at night

and just one peak value in Western Sichuan Plateau in afternoon.There is positive trend between mean percentages of positive CG lightning flashes and mean hail size as hail diameter increases from 3 to 10 mm.The highest average percentages of positive CG lightning flashes i.e.30% corresponds with the 22 mm hail diameter

and the highest probability density is over 37% for 16.98% percentages of positive CG lightning flashes with 10 mm hail diameter.