Abstract: Colorectal cancer (CRC) is the most common malignant gastrointestinal tumor. Early screening and intervention are effective measures to reduce its morbidity and mortality. Compared with colonoscopy, non-invasive liquid biopsy has several advantages, such as easier operation, lower cost, fewer complications, and higher compliance, bringing better social benefits. It is the current research hotspot and breakthrough point in colorectal cancer screening technology. Recently, with the development of multi-omics research technology, fecal and peripheral blood genomic, proteomic and microbiomic tests have been proven to be potentially applied in colorectal cancer screening. Several biomarkers for colorectal cancer screening have been discovered, leading to numerous new non-invasive screening methods. In this review, we consolidate the existing techniques for non-invasive early diagnosis of colorectal cancer in combination with national and international literature reports, and discuss their application value to provide a theoretical basis for further research on early colorectal cancer screening.