Caterpillars, the larvae of butters and moths(Lepidoptera), are enormously important in terrestrial food webs. They are not only the preferred grub for insects, birds, fishes, reptile and amphibian but also engineers of nutrient cycling processes and are the largest natural consumers of vegetation. Even though their major role in the ecosystem, details of biology are poorly known for most species. HECRI(Holoce Ecosystem Conservation Research Institution) has been carried out to identify larvae and to acquire useful biological information of primary endemic insect larvae through rearing from 1997 to 2013. Of these this study is the result about special caterpillars feeding on the foliage Oak Trees (Quercus spp.) which composed 60-70% of broad-leaved forest thereby important component for forest in the Korean Peninsula. Total 297 species belonging to 23 families were collected and identified 101 species belonging to 21 families. Among them Oak Trees-dependent monophagous caterpillars are 247 species belonging to 20 families and polyphagous caterpillars are 50 species belonging to 11 families. The dominant family is Noctuidae(83 species), second is Geometridae(67 species) and followed by Notodontidae(33 species).