Objective Eukaryotes use autophagy pathway to recycle nutrients by degrading misfolded proteins or damaged organelles. This study aims to analyze the function of Medicago autophagy genes in plant response to nutritional stress, and provide a reference for the breeding and improvement of Medicago.Method We focused on the ATG7 gene (Autophagy-related gene 7), which serves as the rate-limiting gene in the autophagy pathway, and investigated the similarities of ATG7 amino acid sequences among different plant species. The overexpression vector of Medicago truncatula MtATG7 gene was transformed to Arabidopsis thaliana, to generate the heterologous overexpression lines 35S::MtATG7 and the complementary lines atg7/35S::MtATG7. The plant resistance to stress and autophagic activity were analyzed.Result Under carbon starvation, atg7/35S::MtATG7 rescued the phenotype of premature leaf senescence of atg7 mutant, and the survival rates of 35S::MtATG7 and atg7/35S::MtATG7 plants were significantly higher than that of wildtype. GFP-ATG8e cleavage assay suggested that atg7/35S::MtATG7 restored the deficiency of autophagic degradation activity in atg7 mutants. Under nitrogen starvation, overexpression of MtATG7 also slowed down the senescence rate of A. thaliana leaves.Conclusion Heterologous overexpression of MtATG7 can enhance the resistance of A. thaliana under carbon and nitrogen starvation, which provides a theoretical basis for further improving Medicago agronomic traits by using MtATG7 gene.