Saline-alkali field is an important reserve of arable land resource in agriculture. However，high salinity-alkalinity severely limits the cultivation of crops on saline-alkali soil. The development of crops suitable for growing in saline-alkali soil would be of significant importance in ensuring the food security. In recent years， salt-tolerant rice varieties have become primary candidates for improvement and exploitation of saline-alkali soil. Therefore，the genetic improvement of salinity tolerance has become an important research area in rice breeding. High-level salt stress inhibits the growth and development of rice at all different stages，causing significant reduction in yield and quality. Study on the molecular mechanism of salinity tolerance is of theoretical significance in guiding the development of salinity-tolerant rice varieties. In this review，we summarize the progress of studies on molecular mechanisms of salinity tolerance in rice which involve ion homeostasis regulation，osmotic regulation，antioxidant regulation，stomatal regulation，and signaling regulation. We further summarize the progress of genetic improvements of salinity tolerance in rice，especially highlighting the characterization of functional genes as negative regulators in salinity tolerance and candidates for genome editing-based molecular improvement. We also discuss future research focuses and experimental strategies that would provide a reference for developing highly salt-tolerant rice varieties with elite agronomic traits.