The base paper of corrugated board is mainly produced from Korean old corrugated container (KOCC), and thus the recycling rate of KOCC is very high. However, there is a problem that the pulp quality is very low while the recycling rate of OCC is high. The fines content in KOCC, the main source of the corrugated board, amounts to nearly the half of the total stock, and its formation increases as recycling process repeats due to the hornification of fiber. There have been attempts to improve the drainage property of OCC by increasing the headbox concentration of the paper machine or by applying drainage-promoting polymer additives. However, these conventional methods have problems of weakened paper strength and lowered converting fitness caused by paper formation hindrance. The strength of linerboard could not be increased in case KOCC is used, because hornified OCC pulp can-not be sufficiently refined due to the lowered drainage property caused by fines formation. We studied about a new technique consisting of froth-flotation for fractionating pulp stock into a long fiber portion and fines fraction. This study will be developed in order to enhance the drainage and strength properties of a recycled OCC pulp by selective treatment of flocculant on fractionated OCC Fines.