The research of plant signal peptides mainly focuses on small molecular peptides. As a key component of intercellular communication, small molecular peptides are mainly involved in signal interference, response pathways, display antimicrobial activity, and interaction with receptor kinases on the surface of cell membranes in the form of ligands, which are enable signal communication between cells. Small peptide molecules are important intercellular signal sensing molecules that are critically involved in regulating growth and development processes and stress responses in response to biotic and abiotic stresses in different organ tissues and developmental stages of plants to coordinate and integrate cellular functions. This review indicates a comprehensive overview of the discovery, structural features, classification system, and functional progress of plant small molecule peptides, and focuses on recent years at home and abroad on the CLE (clavata3/ESR) family of posttranslational small peptides and Ralf (rapid alkalinization factor) family of cysteine rich peptides, provides basic information for indepth studies of plant small molecule peptides and reference for future research directions.