结直肠肿瘤是我国最常见的恶性肿瘤之一，严重危害国民身体健康。通过简单有效的检测方法对目标人群进行筛查，早期诊断结直肠肿瘤，是降低其危害的有效策略。然而，尽管我国结直肠癌筛查取得了较大进展，但仍存在筛查方法敏感度和特异度不足，接受度和依从性较差等问题，影响了筛查效果。液体活检作为近些年来新兴的检测技术，其内涵丰富，可选择的检测靶点多，同时具有取样方便，创伤小，人群接受度高，易于推广和开展的优点，在结直肠肿瘤筛查早诊工作中具有广阔的应用前景。血液ctDNA可提供患者体内肿瘤的全景数据，在早期肿瘤患者体内含量较高，是结直肠肿瘤早诊筛查的重要靶点。

Colorectal tumor is one of the most common malignant tumors in our country and seriously endangers our national health. It is an effective strategy to reduce the harm of colorectal tumors by screening the target population with simple and effective detection methods and early diagnosis. However, although great progress has been made in colorectal cancer screening in China, there are still some problems such as insufficient sensitivity and specificity of screening methods, poor acceptance and compliance, which affect the screening effect. As an emerging detection technology in recent years, liquid biopsy has rich connotations, multiple detection targets to choose from, and advantages such as convenient sampling, less trauma, high population acceptance, and easy promotion and development. It has broad application prospects in the early diagnosis of colorectal tumor screening. Blood ctDNA can provide panoramic data of tumors in patients, which is relatively high in patients with early stage tumors, and is an important target for early colorectal cancer diagnosis and screening.