Abstract: Soybean GmPM31 gene encoding protein is a member of sHSP-CI（Class I） subfamily of plant small molecule heat shock protein. In order to study the biological function of GmPM31 protein in soybean stress tolerance, subcellular localization analysis of GmPM31 protein was performed. Yeast two-hybrid and Bimolecular Fluorescent Complimentary methods were used to verify the interaction between Gm2-MMP and GmPM31 protein in vivo. Plant expression vectors with different missing fragments at the 5′ end of GmPM31 promoter were constructed, and the expression level of drived GUS gene was analyzed by transient expression system in tobacco leaves. GmPM31 gene was transformed into Arabidopsis thaliana by Agrobacterium tumefaciens infection. The results showed that soybean matrix metalloproteinase Gm2-MMP interacts with small molecule heat shock protein GmPM31 in vivo. Compared with the control group, the activity of GUS driven by the P2062 and P1800 promoters was significantly increased under high temperature and high humidity stress at 40 ℃, indicating that-1 800～-1 535 bp region plays a key role in the response of the GmPM31 gene to high temperature and high humidity stress signals. Transgenic Arabidopsis plants overexpressing GmPM31 were propagated, and five T₂-generation Arabidopsis positive plants were screened.