Abstract: Genomic DNA libraries of Anopheles sinensis and Anopheles anthropophagus were constructed.The positive clones suitable for discrimination sibling species of An.sinensis and An.anthropophagus were screened and a clone from An.sinensis DNA library was ceceted and the insert DNA was used as a DNA probe to test dot blot of genomic DNA from An.sinensis and An.anthropophagus.The results showed that the DNA probe hybridized with all stages of An.sinensis DNA,but had very weak hybridization signal with An.anthropophagus DNA.The probe was very sensitive and could delect as little as 7.5ng An.sinensis which represents approximately one-150th part of the total DNA from single mosquito.The results demonstrated that the DNA probe reported here could be used to distinguish species of An.sinensis from An.anthropophagus.