Abstract: Nano-fertilizers refers to a new type of fertilizer produced using nanotechnology, which has structural or functional unit sizes at the nanometer level (1−100 nanometers) or employs nano-carriers to deliver nutrients. Nano-fertilizer products are diverse, with nutrient elements distributed in various forms such as crystalline particles, pore structures, and interfacial assemblies. In China, nano-fertilizers primarily include nano-structured fertilizers, nano slow/controlled-release fertilizers, nano-carbon enhanced fertilizers, and nano-bio composite fertilizers. Nano-structured fertilizers are novel fertilizers produced by processing nutrient elements (macro-elements such as nitrogen, phosphorus, and potassium, or micro-elements such as boron, zinc, and selenium) into particles with sizes ranging from 1 to 100 nm through physical pulverization, chemical synthesis, or biological assembly technologies. Nano slow/controlled-release fertilizers are a new type of fertilizer created by mixing traditional fertilizers with nanometer- or submicron-scale materials (e.g. nano-zeolite, nano-kaolin, and mesoporous nano-silica) as carriers, imparting slow-release properties to the traditional fertilizers. Nano-carbon enhanced fertilizers are functional fertilizers prepared by combining carbon nanomaterials such as carbon dots, graphene, and carbon nanotubes with essential plant nutrients, offering good biocompatibility and application potential. Nano-biocomposite fertilizers integrate live microorganisms such as fungi and bacteria or their extracts with nanoparticles, reducing and encapsulating metal ions under mild conditions to form nanoparticles. Compared to traditional fertilizers, nano-fertilizers possess distinct advantages in several aspects. Their small size, high specific surface area, and excellent slow-release properties enable them to enhance the efficiency of plant nutrient absorption and utilization, minimize soil nutrient loss, and mitigate environmental pollution. These benefits manifest in several ways: boosting photosynthesis by increasing chlorophyll content, optimizing photosystem functionality, and activating Rubisco enzyme activity; precisely regulating nutrient metabolism through the activation of key enzyme systems and hormonal signaling networks, thereby significantly improving nitrogen and phosphorus utilization efficiency; enhancing stress resistance by modulating antioxidant enzyme systems, maintaining ion homeostasis, and activating osmoregulatory substances to effectively mitigate salinity, drought, and pest stresses; and improving soil properties by increasing microbial diversity, enhancing enzyme activity, and immobilizing heavy metals to enhance soil physicochemical characteristics. Despite their advantages, nano-fertilizers face certain limitations in practical application and require further research and optimization. Future research endeavors should focus on the following directions: Firstly, addressing the urgent need to reduce the cost of nano-fertilizer production and facilitate its industrial application. Secondly, developing intelligent, dynamic fertilization recommendation systems tailored to the unique characteristics of nano-fertilizers, thereby improving the precision of matching nano-nutrient supply with crop demand. Thirdly, establishing environmental risk assessment and control systems, such as leveraging machine learning to predict environmental risks and ensure ecological safety. These studies will not only provide a new theoretical foundation for a deeper understanding of nano-fertilizer applications in agriculture and forestry but also offer crucial technical support for achieving sustainable development in these sectors.