Abstract: In order to investigate the hydration degree and damage degree of pumice concrete in the curing stage and freeze-thaw stage in the cold regions. Gain coefficient (Ygp) and damage coefficient (Cgp) are calculated based on the porosity, pore size distribution and fractal dimension of pumice concrete. The critical points of hydration degree and damage degree were obtained by the classification of threshold index, and the gain threshold and damage threshold were determined according to the classification evaluation and macro performance. The results showed that 0.947