Soil salinity is one of the most severe factors restricting plant development and distribution throughout the world. Investigation of salt-tolerant molecular mechanisms in plants will help to enable enhancement of plant salt tolerance using molecular biological techniques. Recently, salt-responsive protein profiles in 19 plant species, represented by the model plants Arabidopsis thaliana and Oryza sativa, have been analyzed. Based on these studies, we highlighted the regulatory mechanisms by analyzing the dynamic changes of proteins in different plant groups (glycophytes and halophytes), tissues/organs (root, aerial part, hypocotyl, radicle, leaf, panicle and gametophore), cells (suspension cells, callus and algae) and subcellular structures (chloroplast, plasma membrane and apoplast). The main salt-responsive mechanisms revealed by proteomics were: (1) halophytes can enhance their salt tolerance by regulating the global metabolic and signal networks, such as cytoskeleton remodeling, ion transport and compartmentation, osmolyte accumulation, reactive oxygen species (ROS) scavenging, signal transduction, photosynthesis and energy metabolism; (2) the aerial parts of plant (such as the leaves, shoots and gametophores), photosynthetic cells (e.g., suspension cells, callus and unicellular algae) can adapt to salinity by regulating photosynthesis, carbohydrate and energy metabolism and ROS scavenging; (3) the underground parts of plant (roots and radicle) can perceive and deliver a stress signal and maintain ion homeostasis by regulating expression of signal transduction- or ion transport-related proteins; (4) the proteins involved in osmolyte biosynthesis, transcription, protein processing and ROS detoxification are changed significantly in panicles; (5) the chloroplasts respond to salt stress by altering photosynthesis, protein processing/turnover, and oxidation balance; (6) the expression of proteins related to cell wall metabolism, stress and defense, and oxidation balance changed significantly in apoplasts; and (7) the membrane proteins involved in the cell membrane structure remodeling, material/ion transport and signal transduction play important roles under salt stress. All of these mechanisms provide new insights into the salt-tolerance of plants.