Current studies have shown that plasma trimethylamine N-oxide (TMAO) level is closely related to the risk of acute myocardial infarction (AMI), that is, the possibility of AMI occurrence is positively correlated with TMAO level. The production of TMAO is mainly due to the transformation of trimethylamine (TMA) through the hepatic flavin-containing monooxygenase. Hence, inhibition of TMA production is essential. Flavonoids are considered to be mainly responsible for the health-promoting effects, and tea is rich in a variety of flavonoids. However, it is not clear that flavonoids from Lu'an GuaPian tea regulate gut microflora by inhibiting TMA-lyase activity to prevent AMI. Sixteen flavonoids from Lu'an GuaPian tea for the treatment of AMI based on the inhibition of TMA-lyase were summarized and screened. Docking results showed kaempferol 3-O-rutinoside had the highest Vina score, which means that it is the most active and can be used as lead compounds for structural modification. PRACTICAL APPLICATIONS: TMAO can be used as a marker of CHD and thus as a potential research object. Lu'an GuaPian tea is one of the top 10 famous teas in China and has the aroma of chestnuts and orchids. The flavonoids in Lu'an GuaPian tea are mainly composed of flavonoid aglycones and flavonoid glycosides. Since flavonoids have cardiovascular protection and can regulate gut microbiota, and gut microbiota is directly related to TMAO, reduction of TMAO level is to inhibit the transformation from TMA to TMAO. Kaempferol 3-O-rutinoside, quercetin 3-O-rhamnosylgalactoside, kaempferol 3-O-rhamnosylgalactoside, and myricetin 3-O-galactoside in Lu'an GuaPian tea have good binding affinities with TMA-lyase.