Abstract: ObjectiveTo investigate the changing trend of lung cancer mortality rate in Nanjing city.MethodsGroup samplings were carried out among the resident of Xuanwu District,Nanjing City,the residents death data since 1970 was analysised.The recent lung cancer mortality rats was predicted by gray model.ResultsThe lung cancer mrotality rate for Xuanwu District,Nanjing City was increased continuously.Lung cancer was in the second place among all malignancy death factors in the 1970s and 1980s,but leaps to the first place since 1990 and accounts for 23.45% among all malignancy death factors between 1997 and 1999.The mortality rate and increasing speed of lung cancer for men was higher than that of wome.It was predicted by gray model prediction that the recent lung cancer mor tality rate for men and wome would reach 47.39%/10⁵ and 22.63/10⁵ respectively until 2000-2002;51.24/10⁵ and 24.27/10⁵ respectively until 2003-2005.Conclusions The lung cancer mortality rate has been raised to the first malignancy death factor in Nanjing.In the coming five years,lung cancer would still have arising trend if no effective measures were adopted.