In recent years, agricultural intensification and the need for reduced fertilizer application have rendered soil remediation and agricultural non-point-source pollution control globally significant. Compared to inefficiently utilized inorganic salt fertilizers, chelated fertilizers are more efficient and environmentally friendly, and have thus attracted considerable attention. In the new international context, more attention is being paid to soil remediation and reductions in agricultural non-point-source pollution, as the demand for high-quality agricultural products increases. Chelating fertilizers may play important roles in these contexts; models of stability and structure are required to provide both the theoretical basis for further development and data supporting continuing research and development. The stability constant reflects the stability of a chelated material; the stability constants of chelates can be calculated mathematically using the generating, Leden, and/or Fronaeus function (s). Although no standard method is yet available for the determination of stability constants, a great deal of relevant work has been performed worldwide. However, most methods are not yet mature, and appropriate stability constant reference values remain controversial. Since most of the fertilizers analyzed used amino acids for chelation, other ligands hardly received attention, potential applications of other ligands should be fully exploited. The molecular structure of a compound determines its properties. Structural characterization contributes to the qualitative analysis of chelated fertilizers, improves the understanding of experimental phenomena, and affects the selection of detective methods. The first consideration is whether the chelate is pure. Even if the levels of impurities are low, reliable structural data can be difficult to obtain. Therefore, we systematically summarize progress in how chelated fertilizer stability is assessed and how such fertilizers are structurally characterized. We focus on the advantages and disadvantages of various processes, outlining the need for future research. And we provide a theoretical basis for the development and effective utilization of chelated fertilizers.