Abstract: Based on overall morphological characters of 49 species and 4 variations of Quercus in China,we measured 25 qualitative and 18 quantitative characters.In cluster analysis,the result revealed that Quercus were divided clearly into five phenetic groups,namely Section Aegilops,Section Quercus,Section Brachylepides,Section Engleriana and Section Echinolepides.Principal components analysis obtained the same result of the cluster analysis,but the cumulation rises slowly and that of the first three principal components presented only 50.4%.These results indicated that the principal taxonomic characters exist in Quercus for taxonomy still,only in the period of evolution,several different phenetic groups were produced in the genus Quercus.The result was useful for identifying closely related species of Quercus as well.The method of numerical taxonomy was significance in taxonomy for Quercus.