Alkali stress, including layers of sresses such as ion toxicity, osmotic stress and extraneous high pH (pH >8.5) injury, is a major abiotic stress that seriously endangers the growth and development of plants and the yield and quality of crops. With the continuous expansion of salinized land in China, the ecological system balance is increasingly seriously damaged. Compared with salt stress, the current understanding of alkali stress is relatively superficial, and the adaptation mechanism of plant alkali stress is even less well understood. Therefore, it is of great practical significance to understand and master the adaptive mechanism of alkali stress and plant response to alkali stress, to explore alkali-resistant germplasm resources for future improving ecological environment, and to cultivate alkali-resistant crop varieties for improving saline-alkali land. Based on the domestic and international progress recently, this paper briefly describes the definition and difference of salt and alkali stress. Morphological changes of different organs and organelles under alkali stress are summarized. The physiological adaptation mechanism of plants to alkali stress through cell metabolism, chemical synthesis and accumulation, and scavenging of reactive oxygen species is described. In addition, the molecular adaptation mechanisms of plants in response to alkali stress are indicated with three aspects: cloning and functional identification of alkali-tolerant genes, utilization of transcriptome technology to explore alkali-tolerant candidate genes, and plant alkali-tolerant mediated by Ca2+ signal system. It is pointed out that although many of candidate genes related to alkali resistance were obtained, fewer genes are actually cloned and explored with functional mechanism. Meanwhile, the research prospect of Multi-Omics which mainly focuses on modification omics in alkali tolerance mechanism of plants are prospected, in order to further provide theoretical basis for exploring new alkali resistance genes and unlocking the functional mechanism.