Forest road is the basical instrument to open up the forests. The forest in Korea shows a poor productivity in alf functions. The aecute reson for this fact might be the lack of forest road (1989 : 0.5m/㏊). Thus, the low forest road density forced to construct thousands km long forest road till 2010. The objective of this study is to build up a appropriate opening-up method for the circumstance of Korean Forestry. This research investigated three main parts : the process of opening up planning with the emphasis of required information and its analysis ; to design and lay out the road network ; evaluation of road network with the monetary and non-monetary aspects. For experimental purpose, firstly the optimum forest road density was calculated with the analytical method. This analysis takes into con-sideration the rate of interest, construction cost, cutting volume and real price (regadless to an extreme inflation) . To evalute the monetary effects, the investment efficiency of four variants(four road networks) were analyzed by the transformation of benefit and cost to present value. Cybernetic idea was applied to estimate and analyze the influence and effect of opening-up with road as a non-mometary aspect. In this method, it was tried to minimize the environmental (ecological) damage and at the same time to maximize the economical profit.