For the conservation of wooden coffin from King Muryeong's Tomb we examined weight change, shrinkage rate, color changes, and permeation expansion according to the permeation pretreatment chemicals by producing experimental samples with similar physical properties. The result shows Dammar 2 %(in xylene) as the most excellent treatment for protecting deformation by contraction and strengthening materials which are also maintaining its original colors of wood. Therefore, we could get strengthening conservation treatments of dried wooden coffin materials by using Dammar.