Flavonoids are abundant in citrus and widely used in food， medicine， cosmetics， and other industries due to its various physiological activities. Flavonoids are mostly extracted from citrus and other plants， and a small amount is synthesized chemically or modified structurally. In recent years， the microbial method of constructing metabolism pathways in a host， such as Escherichia coli and Saccharomyces cerevisiae， has entered the research stage， which has sustainable application prospects due to its high safety， environmental protection. Collectively， this study briefly describes the synthesis of flavonoids in citrus and focuses on the research progress on the microbial synthesis of naringin， hesperidin， eriocitrin， etc. We also propose several problems with the heavy metabolic burden of the host， the low efficiency of gene expression， unreasonable distribution of carbon flux， and put forward solving methods including optimization of the host selection， microbial coculture， the expression system， and carbon flux. We hope to provide references for the current research on the microbial synthesis of flavonoids in citrus.