Abstract: Karrikins, which is a series of natural products isolated from the extracts of plant-derived smoke, can act as signal molecules in plants. They can stimulate seed germination at very low concentrations (< 10⁻⁹ mol/L), demonstrating great potential in agriculture and horticulture. Due to their novel chemical structures, potent biological activity and low concentration in nature, their total syntheses and structure-activity relationship (SAR) research of the Karrikins and analogues have attracted great attention of researchers. In this review, total syntheses and biological activity research of the Karrikins were summarized and reviewed, thus providing effective information for further related research of the Karrikins.