Salt stress is one of the main abiotic stresses affecting plant growth and development. Metalloproteinase FtsH (Filamentation temperature-sensitive H) is a type of ATP and Zn2+ dependent protease in the AAA family of proteases (ATPase associated with various cellular activities), and it plays an important role in plant chloroplast development, photosynthetic system protein synthesis and repair, response and resistance to abiotic stress, leaf noise regulation and other important processes. Although FtsH has been extensively studied in several species such as Arabidopsis thaliana, Brassica napus, Glycine max, its function in Medicago sativa has not been reported. In this study, we cloned and analyzed the expression pattern of MsFtsH8 gene in Medicago sativa, followed by a Bioinformatics analysis of the gene sequence. Over-expression of the gene in A. thaliana significantly increased seed germination rate, root length and fresh weight under salt stress. Collectively, this study provides important candidate genes and theoretical reference for alfalfa molecular breeding regarding to salt tolerance.