Plant wearable sensors (PWSs) can obtain weak plant physiological information under complex agricultural environment in real time and multiple points, offering powerful tools for smart agriculture. However, research on PWSs started relatively late and is strongly interdisciplinary, leaving their development and application still facing challenges. It is therefore necessary to review and trace the evolution of PWSs to clarify their technological trajectory, highlight current progress, and recognize remaining challenges. Herein, PWSs are systematically discussed in terms of their development roadmap, categories, materials, energy-supply technologies, fabrication techniques, and applications. Furthermore, multiscale modeling, such as density functional theory, finite element analysis, and machine learning respectively provides insights from the atomic scale in charge transfer and interfacial interactions, the macro-meso scale in mechanical adaptability and structural reliability, and efficient data analysis, thus advancing the rational design and practical deployment of PWSs. Finally, a systematically curated table, complemented by a comparative radar chart analysis, provides an overview of reported devices by summarizing their key attributes while elucidating strengths and trade-offs for specific applications. This review not only provides guidance for proposing future design strategies and research directions, but also serves as a roadmap for advanced PWSs and facilitating their translation from laboratory research to applications.