Objective:To investigate the efficacy of different conversion therapies for colorectal cancer with unresectable simultaneous liver metastasis.Methods:A total of 170 patients of colorectal cancer complicated with liver metastasis who were admitted to the First Affiliated Hospital of Nanchang University from Jan 2015 to Dec 2020 were included in the study. Patients were divided into an initial resectable group (42 cases) and an initial non-resectable group (128 cases).Results:There were no significant differences in OS and PFS between patients with CRLM (colorectal cancer with liver metastasis) who were resected initially and those successfully underwent transformation therapy ( P>0.05). The median OS was 36 months in the group with successful transformation, while it was 21 months in the group with simple primary tumor resection and no liver metastasis resection ( P=0.014), HR=0.48 (0.27-0.86). The median PFS was 28 months in the successful conversion group, while it was 10 months in the primary tumor resection only and no liver metastasis resection ( P=0.005), HR=0.43 (0.24-0.77). The OS difference between the group with simple primary tumor resection and no resected liver metastasis and the group with neither primary tumor nor liver metastasis resection was statistically significant: (21 months vs.13 months), HR=0.52 (0.32-0.86) ( P=0.01), while the PFS between the two groups was not statistically significant, ( P>0.05). Conclusions:Chemotherapy combined with targeted therapy has the best effect among the conversion therapies, and can improve the resection rate and survival rate of patients undergoing R 0 surgery. Resection of the primary lesion alone can also prolong the patient's survival.