Leaves are important vegetative organs of plants, and leaf margin serration (lobe) has many advantages in production practice. The research on the regulation of leaf margin serration has important guiding significance for plant breeding. This paper reviews the regulation mechanism of leaf margin serration formation. Several factors such as plant hormones, gene expression, and miRNA have role in shaping leaf margins. Auxin unbalanced accumulation at the leaf margin can promote serration. Cytokinins (CK) depends on accumulation of auxin at leaf margin to promote leaf shape complexity, while gibberellin (GA) negatively regulates leaf shape complexity. Meanwhile, this paper summarizes three main pathways of plant hormones and genes involved in leaf margin serration formation: TCP-CUC-PIN1-Auxin, KNOX-GA/CK, LMI1-CK. MiR164, miR319, polycomb group (PcG) epigenetic modification and alpha-1,2-glucosyltransferase are also involved in leaf margin serration formation. Previous studies have shown that ambient temperature and light intensity regulate the leaf margin development through the KNOX-GA pathway. High temperature and low light intensity decrease the complexity of leaf shape. The genetic mechanism of regulation on leaf margin serration differs from plants to plants. The discovery of leaf margin serration related genes mainly focuses on cash crops, as to fruit trees breeding, further research should promote not only fruit quality and resistance but also ornamental character.