Abstract: Stress significantly affect plant growth and development, physiological metabolism, as well as yield and quality. Given their sessile nature, plants have evolved integrated stress resistance strategies that depend on intrinsic physiological regulation and interactions with rhizosphere microorganisms. As a crucial "extended component" of plant phenotypes, the structure and function of the rhizosphere microbiome undergo dynamic remodeling under diverse stress conditions. Plants can selectively enrich and maintain beneficial microorganisms by regulating the composition and intensity of root exudate release. This review summarizes the variation patterns of rhizosphere microbial communities structure and function under stress, the main features and potential mechanisms of microbial selective enrichment mediated by root exudates, and recent studies in how rhizosphere microorganisms enhance plant stress resistance through multiple pathways, including water acquisition and ion homeostasis, nutrient mobilization and uptake, maintenance of photosynthetic capacity, regulation of reactive oxygen species homeostasis, immune priming and disease suppression, and hormone signal reprogramming. Furthermore, current research gaps—such as the identification of key signal molecules, microbial perception and colonization mechanisms, physiological function of key flora, and cross-environment reproducibility—are discussed, and future research directions and application prospects are proposed. This review provides a theoretical basis for a deeper understanding and agriculture utilization of plant–rhizosphere microbiome interactions in plant stress resistance.