Objective To summarize the research progress of MRI in the assessment of rectal cancer before surgery. Methods Literatures about the recent studies on the research progress of MRI in the assessment of rectal cancer before surgery were reviewed according to the results searched from Pubmed, CNKI, and WanFang database. Results Preoperative staging, circumferential resection margin, and extramural vascular invasion were closely related to the prognosis of rectal cancer patients, MRI could provide a good assessment of preoperative staging, circumferential resection margin, and extramural vascular invasion for rectal cancer patients, but it still had some deficiencies which needed further studies. Conclusion Application of MRI in the assessment of preoperative staging, circumferential resection margin, and extramural vascular invasion before surgery, is conducive to the development of the most appropriate treatment options for patients with rectal cancer.