This experiment was conducted to investigate the effect of physical and chemical characteristics of lower grade tobacco with treatment of ozone. In ozonization of low grade tobacco, optimum moisture was 20 percentage, and decrease ratio of content of tobacco leaf was 30 percentage in nicotine , 15.9 percentage in total volatile base, 10.5 percentage in petroleum-ether-extract, 29.5 percentage in solanesol, and decrease ratio of cigarette smoke composition was 31 percentage in nicotine, 6.08 percentage in tar.