【Abstract】ObjectiveTo explore selective criteria of sphincter preservation operation (SPO) for middle to low third rectal cancer, and analyze clinicopathologic parameters resulting in the selective criteria. MethodsTwo hundred and seventynine cases of middle to low third rectal cancer who accepted operative treatment from 1996 to 2004 were analyzed retrospectively. One hundred and eightyseven rectal tumours were located in 5-10 cm from anus, 92 rectal tumours in below 5 cm from anus. Among them 127 cases were treated by abdominalperineal resection (APR), and 152 cases were treated by SPO in which there were 130 Dixon operations, 12 Bacon operations, and 10 Parks operations. Clinicopathologic parameters and survival rate in APR and SPO groups were compared statistically. ResultsGender, age, size, tumor types, site of tumor, degree of differentiation, infiltrated circumference of intestine, and lymph node metastasis, depth of invasion and Dukes stages were not significantly different between APR and SPO groups. SPO performed rate was 54.48% in all. SPO was performed in 48 lower third rectal cancer cases (52.17%, 48/92). Regional recurrence rate was 6.81% (19/279).Middle survival time was (65.00±6.87)months and 5year survival rate was 63.51% in SPO group. Middle survival time was (52.23±5.63) months and 5year survival rate was 52.50% in APR group. ChiSuqare was 18.14 by Logrank test (P=0.054 1). ConclusionThere is no statistically difference in survival rate between APR and SPO groups.