GRP (glycine-rich protein) is characterized by glycine-rich and conserved motifs that include (Gly) N-X repeats. This superfamily is generally divided into five major subclasses. Although GRP has been found to be involved in the stress response in many model plants and nonmodel plant species, little is known about the key physiological processes and molecular mechanisms involved in these proteins. In this study, we identified and analyzed the GhGRP genes of five subgroups of Gossypium hirsutum for the first time. Our research showed that GRP overexpression could enhance the salt stress tolerance of Arabidopsis thaliana and cotton, which would play a very promising role in cotton genetic engineering breeding. The GRP gene had make some progress in rice, Arabidopsis thaliana, maize, tobacco and other plants. In cotton, only Gossypium arboreum and Gossypium raimondii had been analyzed and identified into subgroup IV[(](#ref-0038)W. Yang et al., 2019), also known as the RB-GRP. VIGS and Arabidopsis thaliana overexpression experiments showed that the expression of GRP42 gene could indeed improve plant salt tolerance. The results of TEM showed that GRP42 gene maight act on the cell wall of plant vascular tissue and played a supporting role.