Abstract: Gastric cancer is one of the common malignant tumors worldwide, characteri⁃zed by poor prognosis. Currently, screening, diagnosis and postoperative recurrence monitoring for gastric cancer rely heavily on methods such as endoscopy, imaging and pathological examinations. However, traditional diagnostic approaches have limitations, including invasiveness and low sensi-tivity. Liquid biopsy techniques, with circulating tumor DNA (ctDNA) detection as a representative, can identify and analyze free DNA released into the bloodstream by tumor cells. Liquid biopsy is less invasive and requires smaller sample volumes. Furthermore, ctDNA detection allows for repeated assessments over time, enabling longitudinal monitoring of tumor burden and molecular changes. It has played a crucial role in guiding treatment selection, evaluating treatment efficacy, and monitoring recurrence in various cancer types. Based on the latest literature and clinical practice, the authors elaborate on the research progress of ctDNA detection in gastric cancer.