Objective To observe the expressions of P53 and CD34 in rectal cancer and distal mucosa and to explore the safe distal margin of radical surgery for rectal cancer at molecular pathologic level. Methods Forty-five cases of rectal cancer were marked before operation， and then the cases were detected by PET/CT. P53 and CD34 expressions in rectal tissues were detected by immunohistochemistry technique. Results P53 expression and microvessel density (MVD) in rectal cancer were significantly higher than those in distal mucosa， which in distal mucosa were decreased along the anal direction. P53 and CD34 were still found in the normal rectal tissue. P53 expression and MVD were not significantly different between in more than 1.5 cm distal rectal mucosa and in normal rectal tissue. Besides MVD was related to size of tumor in rectal cancer and distal 0.5 cm rectal mucosa tissue, P53 and CD34 in rectal cancer and distal mucosa rectal tissue were not associated with tumor diameter, stage and differentiation of rectal cancer. Conclusion From the molecular pathologic view, the resection of 2.0 cm rectal distal tissue should be safe for excision of rectal cancer.