Objective To analyze the clinical value of MR diffusion weighted imaging (DWI) combined with serum type IV collagen (COLIV) and carcinoembryonic antigen (CEA) levels in the diagnosis of hepatic matastasis of colorectal cancer. Methods A total of 370 patients with colorectal cancer who were admitted to the hospital during the period from July 2016 to February 2018 were selected as subjects. Patients with hepatic metastases were included in the metastasis group (n=50), and those without were included in the non-metastasis group (n=320). All patients underwent routine MRI and MRI+DWI examinations (b=0, 1000s/mm2 ). The characteristics of MRI images and the apparent diffusion coefficient (ADC) were analyzed. Serum COLIV and CEA levels in both groups were detected. The ADC and serum COLIV and CEA levels were compared among patients with different subtypes of hepatic metastases. The diagnostic efficiency of MRI+DWI combined with serological indicators was analyzed. Results Hepatic metastases showed equal or slightly high signal on T2WI. The signal of some lesions were inhomogeneous, the edges were burred or lobulated. MRI showed equal or slightly lower signals on T1WI, high signal on DWI, low signal on ADC image. When the b value was 1000s/mm2 , the ADC in the metastasis group was lower than that in the non-metastasis group, and serum COLIV and CEA levels in the metastasis group were higher than those in the non-metastasis group (P<0.05). The ADC value of mixed type was less than the desmoplastic type, and less than the push type (P<0.05), while there was no statistically difference in the levels of serum COLIV and CEA among the three subgroups (P>0.05). The sensitivity, specificity, accuracy and kappa value of MRI+DWI combined with serum COLIV and CEA in diagnosis of hepatic matastasis of colorectal cancer were 92.00%, 89.06%, 89.46% and 0.643 relatively, which were higher than those of MRI or MRI + DWI (P<0.05). Conclusion MRI+DWI combined with serum COLIV and CEA can be used to diagnose hepatic matastasis of colorectal cancer.