Abstract: To investigate the important role of mannitol dehydrogenase （MTD） in plant stress responses, in this study, ten MTD genes （VrMTDs） were systematically identified from the mung bean （Vigna radiata（L.）R Wilczek） genome. Comprehensive bioinformatics analyses were conducted on their sequence structures, phylogenetic relationships and physicochemical properties. All VrMTDs possess the highly conserved PLN02586 superfamily domain. Phylogenetic reconstruction revealed that mung bean MTDs cluster closely with homologous genes from soybean, suggesting an independent evolutionary trajectory within legumes. Transcriptome profiling demonstrated distinct organ-specific expression patterns of VrMTDs across roots, stems and leaves. Under cadmium （Cd） stress, several VrMTDs （notably VrMTD2.3, VrMTD2.4, VrMTD2.5 and VrMTD3.1） were significantly upregulated, accompanied by a marked increase in MTD enzyme activity, particularly in roots and leaves. These findings indicate that MTD genes contribute to mung bean Cd-stress tolerance by modulating mannitol metabolism, thereby maintaining cellular osmotic balance and antioxidant capacity. This work provides a theoretical foundation for elucidating the roles of MTD genes in legume stress adaptation.