Abstract: Ferulic acid (FA) is an active component in various traditional Chinese medicines, such as Angelicae sinensis Radix. Previous studies showed that FA exhibits multiple pharmacological activities, including antioxidant, anti-inflammatory, and hypoglycemic effects. Due to its significant antioxidant capacity, FA is utilized as an antioxidant food additive. Additionally, its sodium salt, sodium ferulic, is primarily used in clinic as an adjunct treatment for ischemic cerebrovascular iseases and associated disease. However, its metabolites in human after oral administration have not been thoroughly elucidated. Therefore, this study aims at identifying the metabolites of FA after oral administration and speculating on possible metabolic pathways. Plasma, urine and feces at different times (segments) from subjects with mild cognitive impairment in clinic were collected after oral administration of sodium ferulic. Liquid chromatography coupled with mass spectrometry (LC-MS) combines the high-efficiency separation capabilities of LC with the powerful qualitative analysis advantage of MS, playing a vital and irreplaceable role in the in-depth study of chemical profiles in complex systems. The coupling of a quadrupole with time-of-flight mass spectrometry can offer high sensitivity and high resolution, and has become one of the important analytical tools for the identification of metabolites. In this study, the structural identification of metabolites was conducted using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF MS) under negative ion mode. In order to enhance the structural annotation of metabolites, the in vitro incubation system serving as the classic and simple model for the study of liver metabolic enzymes and drug metabolism, were employed in combining use of available authentic standards, including ferulic acid, caffeic acid, 3-hydroxycinnamic acid, and dihydroferulic acid, to produce the targeted metabolite profiles. In the in vitro incubation system, the focus was on phase I and phase II metabolism, including reduction, hydroxylation, glucuronidation and sulfation of FA. As expected, a total of 10 metabolites are identified with retention time in the in vitro samples. The subsequent LC-MS analysis of the clinic samples identifies 31 metabolites of FA, among which 9 ones are detected in plasma, 15 ones in feces, and 27 compounds in urine. The primary metabolic pathways of FA are enriched to include methylation, demethylation, hydroxylation, dehydroxylation, reduction, glucuronidation, and sulfation of FA. This study systematically identifies the metabolites of FA in vivo, providing scientific evidence and reference for further studies in the pharmacological mechanism of FA.