Abstract: Alfalfa is an important legume forage.However,since the response of alfalfa to salt-alkali stress is both genetically and physiologically complex,it is challenging to study the mechanism of its salt-alkali stress tolerance and how to reduce salt-alkali stress and give full play to its advantages.This study was based on molecular biology methods,such as the transcriptomics,proteomics and metabolomics,expounds the mechanism of salt tolerance of alfalfa and slow the physiological reaction of salinity-alkalinity stress,and discussed the application of the mechanism of salinity tolerance of alfalfa potential,so as to the salt-tolerant mechanism of alfalfa under salinity stress,ease salinityalkalinity stress damage and alfalfa planting provided reference.