<正> The dissolved quantity of 10 Na2O.18B2O3-72 SiO2(mol%) glass was measured and the-change of the un-and attacked surface of this glass by water was observed with photometric analysis and IRRS.ESCA methods. The corrosion mechanism of this glass was put forward. It has shown that the process which this glass was corroded in the water could be divided into two stages with the dissolved quantity-square root of time behaviour. Firstly the stable colloid film containing[BSiO4]-constitution was formed due to the leaching of Na2O and[BO3/2] trihedral constitution from the surface during the period of 0~120min. Secondly the Na2O and[BO3/2] trihedral constitution was leached through the loose colloid film continually, the colloid film was destroied because [BSiO4]- was isolated and dissolved daring the period of 120~180min.