Seeds undoubtedly play an essential role in the storage of germplasm resources preserved both to facilitate the preservation of rare species and genetic innovation. However, the negative effects of seed aging and deterioration on crop yield and quality, which negatively affects the germination rate, seed vigor and viability, embryo growth, and seedling emergence of future generations of seeds, has become a cause of increasing concern. In addition, problems associated with seed aging can also accelerate the loss of global biodiversity, grassland degradation, and desertification, because of the poor quality germplasm and dysfunction of the soil seed bank. This article summarizes current research on the physiological characteristics of naturally and artificially aged seeds and their various intrinsic chemical alterations, including their protective enzymatic activity, nucleic acid and protein content, endogenous hormones, and plasma membrane integrity. We also comprehensively interpret advances in research on the aging mechanism, including aspects of protein and nucleotide metabolism, seed moisture content, and genetic recombination. This work is intended to provide a theoretical reference for future exploration of seed aging, and insight into potential repair and lifespan elongation methods.(1) Seed moisture content should be a focus of future studies, because the biophysical status and quantity of the water in aged seeds determine the different pathways of seed death or deterioration. Furthermore, activation of ROS (reactive oxygen species) can significantly accelerate the aging process, particularly when seeds are hydrated, as this endows them with mobility and increases biological activity. In addition, ROS play a positive role as intracellular signaling molecules in seed germination and other physiological processes. Thus, real-time, continuous, and qualitative-quantitative analyses and monitoring of the ROS distribution in different embryo components may help to reveal the comprehensive and multiple functions of ROS during seed aging. Moreover, as mitochondria have been well established as the main organelle via which to detect ROS accumulation, detailed examinations of their physiological changes before and after aging (naturally and artificially induced) may provide a more specific target for the study of PCD (Programmed Cell Death) occurring during seed aging.(2) Enzymatic or non-enzymatic reactions can result in seed aging. Thus, observing and regulating the metabolism and signal transduction pathways of biological enzymes accelerating the aging process at the proteomics, transcriptional, and gene recombination levels could be a promising strategy for future seed aging research. Relevant enzymes include PLD (Phospholipases D) and LOX (lipoxygenase). Therefore, comparing the physiological and biochemical changes,from aspects of matter and energy metabolism, redox potential, protein expression, and nucleic acid metabolism, involved in different parts of the aged seeds (hypocotyl,cotyledon, endosperm), and different periods of aging process (aged in the early, middle, late) is a necessity to gain a better understanding of aging mechanism. Nevertheless, current attention has mostly been on traditional and fragmentary reaction procedures as well as the internal and external factors that influence the aging process. Some perspective studies, which are more systematic and multidimensional, may facilitate the development of targeted research on seed aging. This in turn could prompt the development of biotechnological advances for organismal biology and the seed aging mechanism.