Abstract: Inositol, as a biostimulant, plays a crucial role in signal transduction, nutrient storage, and stress protection in plants, and can systematically enhance plant nutrient utilization efficiency. Investigating the mechanisms by which inositol regulates nutrient signaling and resistance to abiotic stress, as well as elucidating its potential applications for enhancing plant stress tolerance, can provide new ideas for developing stress-resistant crops and novel green intelligent fertilizers, contributing to green agriculture development. This review systematically summarizes the biological functions of inositol, particularly its involvement in plant nutrient regulation and phosphorus signaling. At the same time, it affects plant growth and stress resistance response by coordinating auxin and jasmonic acid signaling pathways. Moreover, under abiotic stresses such as salinity and alkalinity, inositol enhances plant stress resistance by participating in the clearance of reactive oxygen species in the body and promoting the accumulation of osmoprotectants, providing important insights into the mechanism by which inositol regulates plant stress resistance. Inositol and its metabolic derivatives can regulate cellular signal transduction and enhance the ability of plants to resist abiotic stress. However, the role of inositol in plant nutrient transport and the molecular mechanism underlying its regulation of signaling pathways remain unclear. Meanwhile, studies on the application methods and field effectiveness of inositol-containing fertilizers are limited. The research on the industrial development of related fertilizer products requires further strengthening.