Abstract: The specific surface area is an important parameter for evaluating the release of radio nuclides from the HLW glass in the deep geological formation. Inverse gas chromatography (IGC) was used to study the specific surface area of the HLW glass for the first time. The result shows that the specific surface area of the glass increases quickly at the early immersion period and then keeps stable. Depend on the glass surface area to immersion water volume (S/V), the stabled specific surface area could be increased to 100, 50 and 10 times of that of the glass without immersion corresponding to S/V of 1 500, 3 000 and 6 000 m^-1. For the first time, the irreversible adsorption amounts of the probe on the corroded glass were applied for the characterization of the surface heterogeneity. The proportion of the heterogeneous morphology of the corroded glass reaches to 20%-40%.