Abstract: In order to study the inhibitory effect of the active ingredients of the Flemigia philippinensis roots on acetylcholinesterase (AChE), the roots of the Flemigia philippinensis were used as raw materials, and different solvent systems were applied to fractionate and extract flavonoids, and then further separate and purify them. Reversible inhibition kinetics method were applied to study the inhibitory effect of different solvent extracts and four flavonoids on AChE and related constants. The results showed that the different solvent extracts and the four favonoids (Genistein, Philippin C, Philippin D and Flemiphilippinone A) from the roots of Flemigia philippinensis had a strong inhibitory effect on AChE. The inhibition type was mixed type inhibition, and the half inhibition concentration (IC₅₀) was (57.86±0.67)~(127.28±1.22) µmol/L, the inhibition constant K_i was (54.8±0.43)~(120.58±1.35) µmol/L. The research results could provide a theoretical basis and experimental basis for the discovery of high-efficiency acetylcholinesterase inhibitor lead compounds and the development and comprehensive utilization of Flemigia philippinensis related foods.