Contact-metamorphosed calc-silicate hornfels of the Hwanggangni formation adjacent to Daeyasan granite in Goesan are characterized by the mineral assemblages. tremolite-clinozoisite-alkali feldspar-calcite, diopside-grossular-vesuvianite, and wollastonite-diopside-phlogopite-grossular-vesuvianite, indicating low $X_{CO_2}$ condition during contact metamorphism. Two trends of fluid-rock interactions are recognized; combination of infiltration and buffering in the outer portion of the aureole and fluid-dominated behavior in the most part of the aureole. Modal abundance of diopside produced during metamorphism was measured in order to estimate fluid/rock ratios and permeabilities with the assumption that equivalent volume of fluids estimated from the fluid/rock ratios flow through the rock body. The calculated fluid/rock rations and permeabilities range from 0.6 to 9 and $10^{-19}$ to $10^{-17}$ meabilities in the calc-silicate hosted contact aureoles and expected values during progressive metamorphism by theories.