Salt stress is one of the most important abiotic stresses, which seriously threatens the growth and development of plants. Understanding the adaptive mechanisms of plant to salt stress is beneficial for the breeding of salt tolerant crops and the effective use of saline land to meet the increasing demand of food supply. Salt stress causes ion imbalance, osmotic derangement, and accumulation of toxic substances, especially reactive oxygen species (ROS), in plants. To adapt to salt stress, the plants have to balance cellular ions, remodel osmotic potential and maintain ROS. The former researches on the genetic, physiological and biochemical subjects have revealed a large number of plant regulators responding salt stresses, which might modulate plant salt tolerance through multiple and complex stress signal pathways. This paper reviews the salt sensing, signal transduction, gene expression regulation, phytohormone regulation and adaptive response of plants under salt stress, and provides a relatively complete summary of plant salt stress response mechanisms.