SLC has installed and operated a 50 tons/day scale pilot plant of construction & demolition waste (c&d waste) separation/ selection pilot plant in order to utilize wood wastes among construction wastes carried into landfill sites as energy sources, etc. In the present study, for optimized operation of the aforementioned pilot plant, the characteristics of operation of the plant were assessed in relation to changes in operation conditions and the characteristics of inputted wastes. Based on the results of an experiment conducted to select sieves of vibrating screens for the discharge of incombustible materials, wood waste recovery rates were the highest when 8mm sieves were applied but the purity of wood wastes and combustible materials was higher when 20 mm sieves were applied. By supplementing the shape of the overflower of the wet separator, combustible materials stagnant in the water tank were reduced and the rate of recovery of combustible materials including wood was improved by around 10%. It was identified that not only the amounts of wood wastes and combustible materials among inputted wastes but also the ratio of coarse combustible materials to entire combustible materials could affect operation time. Therefore, if processes to select or smash coarse combustible materials in advance are added and bottle neck points are supplemented to be prepared for an increases in the amount of inputted combustible materials, construction wood waste selection/separation facilities could be stably operated even when the characteristics of inputted wastes are changed.