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Flavonoids have good pharmacological activity and are widely used, but the yield of extracted flavonoids is low and the price is high. In order to explore the new technology of artificial synthesis of flavonoids and synthesis of new flavonoids, natural product paeonol was used as the raw material, and alkali catalyzed condensation reaction between m-hydroxybenzaldehyde and paeonol was carried out to construct intermediate product Ⅰ. Then, at high temperature, dimethyl sulfoxide (DMSO) was used as a solvent, and iodine was catalyzed to induce its oxidation and cyclization to obtain the target product Ⅱ. The structure of the product was determined through comprehensive analysis such as UV, IR, elemental analysis, and nuclear magnetic resonance. The changes in UV spectra of product Ⅰ and product Ⅱ in different concentrations of acid, alkali, and salt solutions were investigated and the reasons were analyzed. The results show that product Ⅰ is 2′,3-dihydroxy-4′-methoxychalone, with a yield of 82.2%. Its UV spectrum varies in different concentrations of acid, alkali, and salt solutions, and it could react with low concentrations of NaOH solution. The product could exist stably within 30 minutes and also easily interact with KNO3 solution, resulting in unstable products. Product Ⅱ is 7-methoxy-3′- hydroxyflavone, with a yield of 92. 0% . It can exist stably for a long time in HCl (4.0 mol / L), NaOH, and KNO3 solutions. This synthesis process overcomes the problem of protecting hydroxyl groups in condensation reactions and achieves efficient synthesis of 7- methoxy-3′-hydroxyflavones. Product Ⅰ failed to form a 4-chromone structure, with one phenolic hydroxyl group on each AB ring. Its stability is greatly affected by the environment, especially in alkaline environments. When using product Ⅰ, the storage environment should be controlled, and the pH should not be higher than 7. Product Ⅱ has a stable conjugated structure, which is less affected by the environment and can also exist stably in strong acid environments. This study has guiding and reference value for the production and application of flavonoids. [ABSTRACT FROM AUTHOR]