Tumor heterogeneity reflects clonal evolution and is an important driving force for tumor progression, metastases and drug resistance, which becomes a big challenge for the effectiveness of personalized cancer therapy. Recent studies highlighted multiregional sequencing approach, which sequences DNA samples from geographically separated regions of tumors from a single patient, for exploring the nature of intratumor heterogeneity (ITH) and cancer evolution. Some large-scale sequencing studies have systematically revealed that ITH as well as cancer evolution of non-small-cell lung cancer and renal cancer. However, large-scale sequencing studies of Colorectal Cancer (CRC) have been limited. In addition, most of the ITH studies of CRC were performed at relatively shallow depths, which was not possible to assess heterogeneity due to the inability to detect somatic mutations with low frequencies. In this prospective study, we performed multi-region whole-exome sequencing with high depth on early-stage colorectal tumors from 68 CRC patients (18 right-sided colon cancers, 20 left-sided colon cancers, and 30 rectal cancers patients). These early-stage colorectal tumors had been surgically resected before starting any systemic therapy. We sequenced and analyzed 206 tumor regions including multi-regions of primary tumor together with lymph node metastasis and extranodal tumor deposits (ENTDs). Our study pictures the evolution pattern of CRC with ITH.