Abstract: Chemotherapy is dominated treatment measure in metastatic colorectal carcinoma and irinotecan is one of effective chemotherapy drugs. However， the disadvantage of irinotecan is limited effect and varied adverse effects in different patients. So it is of great importance to explore effective bio-markers and screen the patients who potential benefit from irinotecan with good tolerance. The gene polymorphism of UGT1A is closely related to the adverse effects and benefit of irinotecan with controversial analysis results. This review referred the limitation of UGT1A gene polymorphisms prediction to irinotecan. It might be accounted for ethnicity， dose， drugs used in combination or targeted drugs. It is a more effective pattern to predict the benefit and adverse effects by combined gene polymorphism examination of CES， ATP blinding cassette transporter， CYP3A4， SCOL and so on.