Due to industrial development and increasing pollution from domestic wastes，heavy metal concentrations in crops are exceeding standards，posing a serious threat to human health. Aluminum-activated malate transporters （ALMT） encode a class of anion channel proteins that play important roles in the transmembrane transport of plant organic acids. In order to investigate the function of GmALMT33 gene in response to Cd stress in soybean， the GmALMT33 gene was cloned from soybean using RT-PCR in this study. The CDS region of the gene is 1622 bp in lengh， encodes 553 amino acids，and contains the ALMT structural domain. qRT-PCR results showed that the expression level of GmALMT33 was the highest in the roots of soybeans，and the expression of this gene showed a tendency of first increasing and then decreasing after cadmium stress. We constructed the plant expression vector pCPB-GmALMT33 and genetically transformed tobacco and soybean hairy roots. Phenotypic analysis of the transgenic plants showed that under cadmium stress （66 μmol/L CdCl₂），the leaf blades of the transgenic tobacco were yellowed and greenish，and the degree of browning at the edges was significantly lower than that of wild-type tobacco. The transgenic soybean hairy root complex plants showed significantly weaker degree of reddish-brown toxicity symptoms in stalks and leaf veins than the trans-space vector plants，which indicated that the GmALMT33 gene improved the toxicity symptoms of transgenic soybean hairy root complex.After 7 d of cadmium stress treatment，the SOD，APX activity and soluble sugar content of transgenic tobacco leaves were higher than those of the wild-type control， and the MDA content was lower than that of the control. After 0 d，1 d and 3 d of cadmium stress treatment，the SOD，APX activity and soluble sugar content of roots and leaves of transgenic soybean hairy root complex were higher than those of the trans-space vector control，and the MDA content was lower than that of the control. GmALMT33 gene improved the cadmium tolerance ability of plants. This study provides a basis for further exploring the mechanism of action of GmALMT33 gene and provides a new gene for soybean stress tolerance breeding.