In recent years, in many places of Anhui, the base of wheat mildew and produce much black mould. Using tissue culture method to explore this unknown pathogen, the pathogen is inoculated to Bangladesh red culture medium after being treated with 70% alcohol, 0.1% silver nitrate and sterile water, and then placing in 25 ℃ constant temperature incubator, observing and analyzing colony morphology, diameter, etc. every five days. And observing the shape of conidium by microscope to identify the unknown pathogen was Alternaria tenuissima. It’s definitude basically that camphor and litsea cubeba oil have inhibition to the pathogen by traditional Chinese medicine fumigation methods which provide scientific guidance for storage of wheat not suffering from the infection of Alternaria tenuissima.