Fruquintinib is a novel oral small molecule compound discovered and developed by Hutchison MediPharma that selectively inhibits vascular endothelial growth factor receptors (VEGFR) 1, 2, and 3 and has demonstrated potent inhibitory effects on multiple human tumor xenografts.Based on first-in-human study, both 4mg QD and 5mg 3wks on/1wk off are safety and efficacy, this phase Ib study is to evaluable the safety, tolerability and efficacy of these 2 regimens with mCRC failed 2nd therapy or more and to determine the recommended dose and regimen in phase II/III study.