The objective of this study was to investigate stability of Korean Paper(Hanji) which is being sold in the Korean markets according to aging treatment. In order to know the aging characteristics, the optical and mechanical properties of before and after wet and dry-heat aging treatment were examined. The optical and mechanical properties were shown higher reduction in the dry-heat aging treatment compared to the wet-heat aging treatment. The Soonji (pure mulberry Hanji) made from black mulberry bast pulp was shown a great reduction of the brightness and whiteness, and increase of the opacity in the aging treatment. On the other hand, in case of mechanical properties, the breaking length of Soonji made from white mulberry bast pulp was significantly higher than that of the others, and the tensile strength was shown drastic reduction in according to Soonji made from black mulberry bast pulp in the aging treatment. The burst strength of Soonji made from black and white mulberry bast pulp was shown the similar value in the wet-heat aging treatment. The folding endurance of Soonji made from white mulberry bast pulp was significantly higher than that of others before and after aging treatment. Consequently, Hanji was affected sensitive in the temperature compared to the humidity. Meanwhile, the density and color of the chinese ink was no significant changes before and after wet and dry-heat aging treatment.