Trimethylamine N-oxide (TMAO) is a small-molecule organic compound. Clinical studies over the past decade have shown that elevated blood levels of TMAO are positively correlated with an increased risk of cardiovascular diseases (CVD). Vascular remodeling (VR) is a critical pathophysiological process in the progression of CVD and is widely involved in the onset and development of conditions such as hypertension and atherosclerosis. Current research indicates that TMAO participates in regulating the process of VR through various mechanisms, including promoting inflammatory responses, enhancing oxidative stress, and inducing vascular endothelial dysfunction. Present interventional strategies targeting TMAO primarily focus on microbial modulation. This review summarizes the sources and metabolic pathways of TMAO, outlines its potential pathogenic mechanisms in VR, and explores the role of TMAO in VR as well as its potential value as a therapeutic target, aiming to provide a theoretical reference for related medical research.