Objective To investigate the application value of biological mesh in the pelvic floor reconstruction of extralevator abdominoperineal excision (ELAPE) for advanced low rectal cancer (RC).Methods The retrospective cohort study was conducted.The clinicopathological data of 228 patients with advanced low RC who underwent ELAPE in the Beijing Chaoyang Hospital of Capital Medical University between August 2008 and December 2016 were collected.Of 228 patients,174 using biological mesh closure and 54 using primary closure were respectively allocated into the biological mesh group and primary closure group.Observation indicators:(1)intra-and post-operative situations;(2) postoperative complications (including short-term and long-term complications);(3) follow-up and survival situations.Follow-up using outpatient examination and telephone interview was performed to detect postoperative long-term complications,tumor recurrence or metastasis and overall survival up to December,2017.Measurement data with normal distribution were represented as（ x） ±s,and comparison between groups was analyzed using the independent-sample t test.Measurement data with skewed distribution were described as M (range),and comparison between groups was analyzed using the nonparametric test.Comparisons of count data were evaluated by the chi-square test or Fisher exact probability.Results (1)Intra-and post-operative situations:all the patients underwent successful ELAPE.The perineal operation time,time of indwelling perineal drainage-tube and hospital expenses were respectively (60 ± 50)minutes,(11.6 ± 2.4) days,(57 781± 11 337) yuan in the biological mesh group and (50±21) minutes,(8.9± 1.7) days,(53 714± 13 395)yuan in the primary closure group,with statistically significant differences between groups (t =3.327,7.691,-2.203,P＜0.05).The total operation time and duration of postoperative hospital stay were respectively (242±53) minutes,(13.0±5.0) days in the biological mesh group and (228±51) minutes,(12.0±5.0) days in the primary closure group,with no statistically significant difference between groups (t =1.701,1.309,P＞0.05).(2) Postoperative complications:26 and 19 patients in the biological mesh group and primary closure group had respectively perineal wound complications (1 patient combined with multiple complications),showing a statistically significant difference between groups (x2 =10.660,P＜0.05).The perineal wound infection,perineal hernia and disruption of perineal wound were respectively detected in 20,6,1 patients in the biological mesh group and 12,7,3 patients in the primary closure group,showing statistically significant differences between groups (x2 =3.931,5.282,P＜0.05).(3) Follow-up and survival situations:174 patients in the biological mesh group were followed up for 64 months (range,13-112 months),and 54 patients in the primary closure group were followed up for 51 months (range,23-76 months).The local recurrence rate,distal metastasis rate and overall survival rate were respectively 5.17％ (9/174),20.11％ (35/174),77.59％ (135/174) in the biological mesh group and 7.41％(4/54),24.07％(13/54),79.63％(43/54) in the primary closure group,with no statistically significant difference between groups (x2 =0.080,0.389,0.101,P＞0.05).Conclusions The biological mesh in the pelvic floor reconstruction of ELAPE for advanced low RC is safe and feasible.Compared with primary closure,biological mesh closure will extend perineal operation time and time of indwelling perineal drainage-tube,and increase hospital expenses,but doesn't affect total operation time and duration of postoperative hospital stay,meanwhile,it can also reduce the overall perineal wound complications,especially in perineal wound infection,perineal hernia and disruption of perineal wound.