Abstract:Streptomyces is a genus of high GC content Actinomycetes with a complex morphological differentiation cycle and strong secondary metabolism ability. It can use the precursor compounds and energy produced by its primary metabolism to synthesize a variety of complex structure, diverse function and biologically active secondary metabolites, which has important value in the fields of agriculture, food, animal husbandry, industry, and medical research. The late morphologic differentiation of Streptomyces is often accompanied by the biosynthesis of secondary metabolites, both of which are regulated by complex networks, and the morphology of Streptomyces has a great impact on the yield of secondary metabolites. A comprehensive understanding of the growth cycle of Streptomyces will deepen the knowledge of the relationship between Streptomyces morphological differentiation and secondary metabolite synthesis. In this paper, we review the process of morphological differentiation, the common regulatory factors involving in morphological differentiation and antibiotic synthesis, and the relationship between Streptomyces morphology and yield, which will help us to better understand the process of antibiotic synthesis. It will also inspire the insights about shortening the fermentation cycle, the construction of high-yield engineered strains, the research and development of new fungicides and the synthesis of new antibiotics.