14 isolates of Exserohilum turcicum collected from 5 provinces of Hebei,Liaoning,Heilongjiang,Shandong,Jilin were cultured in liquid medium,DNA was isolated from the hyphae by CTAB method and were detected on 752-ultravioiet spectrometer,then the DNA were amplificated on thermal cycler PE-4800.The results showed that the ratios of OD_ 260/OD_ 280 of DNA range from 1.730 to 1.847, and clear amplification maps were obtained after agarose gel electrophoresis. It concludes that the CTAB method was more effect...