Abstract: Objective: The inadequate range of operation excise is one of the main reasons of rectum carcinoma part relapse after operation. To elucidate the role of cell proliferation dynamics in the relapse after operation we examined the state of cell proliferation dynamics of 60 rectum carcinoma incisal margin tissues after Dixon operation. Methods: The carcinoma incisal margin tissues embedded in paraffin were sectioned, dewaxing in xylene, dedenzened in gradually ethanol. After rehydrated, the sections were digested with pepsin, filtered, centrifuged, discarded the suspension and dyed with propidium iodide. To examine the DNA index (DI), Synthetic phase fraction (SPF), Proliferative index (PI) of carcinoma tissues and incisal margin tissues with Flow cytometry (FCM). Results: In no-relapse group carcinoma incisal margin tissues, DI is 1.09±0.03, SPF is 4.18±1.32, PI is 8.69±2.13 respectively. In relapse group carcinoma incisal margin tissues, DI is 1.23±0.11, SPF is 10.98±3.12, PI is 14.13±3.67 respectively. By the t test analysis, SPF and PI showed highly significant difference between relapse and no-relapse group (P<0.01). Conclusion: The cell proliferation dynamics may act as a important factor of rectum carcinoma relapse. The range of operation should consider both the distance of carcinoma infiltrate in intestinal wall and all high proliferation mucosa tissue of peripheral carcinoma tissues.