Abstract: Blue mold is a very important tobacco disease in North American. It is caused by Peronospora tabacina ( Adam) and does not occur in China . Chinese tobacco industry could suffer serious losses should the pathogen be introduced and become established. Chinese government and tobacco scientists and workers have paid great attentions to its researches and occurrences. This paper discusses the forecasting long- range transport of tobacco blue mold spores in several aspects in order to prohibit the introduction of this disease.