The present study evaluated the clinical potential of magnetic resonance (MR) diffusion-weighted imaging (DWI) in the diagnosis of rectal cancer.A total of 84 patients confirmed with rectal cancer were used as study subjects in the present study. All patients received conventional sequence MR T1WI, T2WI, and DWI examination as well as operative pathological examination. The differences between the MRI results and operative pathological results were analyzed.The diagnosis accordance rates of conventional sequence examination in stage T1, T2, T3, and T4 were 60.00%, 82.75%, 62.85%, and 80.00%, respectively. The diagnosis accordance rates of conventional sequence combined with DWI examination in stages T1, T2, T3, and T4 were 100.00%, 100.00%, 82.85%, and 100.00% respectively. The total diagnosis accordance rates in the T staging of rectal cancer with conventional (Routinely or generally applied) sequence examination and conventional sequence combined with DWI examination were 71.42% and 92.85%, respectively.The analysis on consistency of MR conventional sequence examination suggested that the conventional sequence combined with DWI examination is more consistent with pathological staging when compared with the convention sequence examination alone. MR DWI combined with conventional sequences reveals quite good accuracy in the T staging of rectal cancer.