 Liver metastasis is the most important prognostic factor of colorectal cancer. Reasonable multidisciplinary therapy might improve the prognosis of patients with liver metastasis. Surgery has been the first choice under such situation. Recently, neoadjuvant chemotherapy has also shown its value in unresectable liver metastasis, for it can increase the chance of R0 resection and give some clues to chemosensitivity of agents. However, for those resectable lesions, the role and safety of neoadjuvant chemotherapy has yet to be confirmed. so we design this study. 