Salinity is a major environmental factor limiting plant growth. The paper summarized the research progress of the effects of salt stress on plant. Analysised the mechanism of the hurt to plant by salt stress, including the produce of free radical,the membrane lipid peroxidation,the hurt of inorganic ions,the hurt of infiltration and accumulation of toxicant .Expatiated the research on the mechanism of the resistance of the plant to salinity. The physiological factors of plant to salt stress been Summarized.