Abstract: Leaf-size classes of 337 vascular plants in Quercus mongolica community in northeast, China were analyzed according to Raunkiaer system. The dominant type was microphyll which percentage is 45.4%,followed by compound leaf (23.1%),mesophyll (22.6%),nanophyll (6.8%),macrophyll (0.9%),aphyllous (0.9%),leptophyll (0.3%).The leaves edges of 337 plants were investigated and the percentage of entire leaves plants is 22.3%.Leaf-size classes spectra of trees,shrubs and herbs were figured out.The mesophyll ratio in trees was higher than that in shrubs and herbs.The mesophyll ratio in shrubs was the lowest.Different sites had different leaf-size classes spectra.Microphyll also was the dominant type in every site.No significant relationships were found between leaf-size classes spectra and latitude and altitued.