Patients with stage Ⅰ colorectal cancer or stage Ⅱ colon cancer usually have a good prognosis and are not recommended to receive adjuvant chemotherapy after radical surgery. With the advances in liquid biopsy technology, detection of circulating tumor DNA (ctDNA) can effectively identify early-stage cancer patients with minimal residual disease (MRD) after surgery. According to the growing number of MRD studies in solid tumor, colorectal cancer patients with ctDNA-MRD detection have a poor clinical outcome and are likely to relapse within two years. This study aims to assess the efficacy of adjuvant chemotherapy with capecitabine plus oxaliplatin (CAPEOX) compared with conventional observation in MRD-positive patients with stage I colorectal cancer and clinically low-risk stage II colon cancer.