Abstract： Objective To analyze the evaluation value of routine MRI examination and diffusion-weighted imaging for preoperative staging of rectal cancer.Methods 155 patients with rectal cancer surgery were selected as the study object,and all patients underwent conventional MRI and diffusion-weighted imaging scan,and compared with the pathological results.Results Routine MRI compared the diagnostic and pathological findings in T,N and M with DWI(P＞0.05).There was no statistical difference between sensitivity,specificity,accuracy,positive predictive value,negative predictive value and pathological results(P＞0.05).Conclusion For patients underwent rectal cancer surgery,conventional MRI examination and diffusion-weighted ima-ging can determine the stage and metastasis of the tumor,and provide data support for the surgery.