This study is focused on the impact of oxygen on chemical oxidation(alkalinity oxidation,acidity oxidation) of tea polyphenol.The results showed that the theaflavin could be obtained by alkali oxidation or acid oxidation of tea polyphenol in three conditions: vacuum,air exposing and oxygen infusion.The more oxygen in the reaction,the more theaflavins were produced.Furthermore,the principal part of chemical oxidation were EGCG、EGC、C、EC.Therefore,oxygen was the important factor in the reaction of chemical oxidation of tea polyphenol.But this was rarely reported.In addition,the yield of alkali oxidation was more than the acid oxidation.This paper reviews the impact of oxygen on chemical oxidation in the preparation of theaflavins for the first time.It lays the foundation for in-depth study of mechanism and preparation of theaflavins formation.