In order to study the durability of fly ash recycled concrete in alpine and saline soil areas, using the mixed solution of 3% NaCl and 5% Na₂SO₄ by mass fraction as the freeze-thaw medium, the freeze-thaw cycle test was carried out on recycled concrete with different fly ash contents by the quick freezing method. The mass loss, compressive strength and relative dynamic elastic modulus of each group of recycled concrete specimens are measured, and the performance degradation law of fly ash recycled concrete under the coupling action of freeze-thaw and compound salt erosion is studied, and durability life of recycled concrete is predicted by parabolic damage model. The research results show that under the action of salt freezing erosion, the relative dynamic elastic modulus and compressive strength of recycled concrete with different contents of fly ash show a trend of gentle decline in the early stage and rapid decline in the later stage, while the mass loss rate increases slowly in the early stage, and increased rapidly in the later period; the parabolic model can better characterize the freeze-thaw damage of fly ash recycled concrete in the compound salt environment, and the model fitting curve is in good agreement with the test results and has high accuracy; When it is 20%, recycled concrete has the longest durability life in the salt-freezing environment.