Colorectal cancer remains one of the most common malignancies in China and continues to impose a heavy disease burden. Because early screening is still insufficient in some populations, a proportion of patients are already at an advanced stage at diagnosis, and further improving prognosis remains difficult. Liquid biopsy uses blood or other body fluid samples to detect tumor-related information, mainly through biomarkers such as circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), and tumor-educated platelets (TEPs). At the current stage, liquid biopsy should be viewed more as a useful supplement to colonoscopy rather than as a replacement. Clinically, liquid biopsy may find applications in screening triage, postoperative monitoring of minimal residual disease, and recurrence risk assessment. Among the circulating biomarkers, ctDNA is supported by more robust evidence and is closer to clinical translation, particularly in minimal residual disease detection and adjuvant treatment decision-making. CTCs can offer cellular-level information on tumour morphology and function, but their clinical use remains constrained by low abundance, pronounced heterogeneity, and a lack of assay standardisation. Tumour-educated platelets are readily accessible and carry abundant RNA-related information; however, their clinical value still awaits confirmation in larger, well-designed studies. Future efforts should prioritise improving the sensitivity of early detection, establishing standardised testing workflows, reducing costs, and conducting prospective investigations, so that the role of liquid biopsy can be more clearly delineated across different clinical scenarios.