Objective To investigate the incidence and influence factors of chronic postoperative inguinal pain (CPIP) after tension-free repair for inguinal hernia.Methods The retrospective case-control study was conducted.The clinicopathological data of 1 188 patients who underwent tension-free repair for inguinal hernia in the People's Hospital of Xinjiang Uygur Autonomous Region between January 2011 and August 2017 were collected.Observation indicators:(1) surgical and postoperative situations;(2) follow-up;(3) influence factors analysis of CPIP.Follow-up using outpatient examination and telephone interview was performed to detect inguinal pain and complications at 1,3,6 months and 1 year postoperatively up to August 2018.Measurement data with normal distribution were represented as x ±s.Measurement data with skewed distrubution were described as M (range).The univariate and multivariate analysis were done using the chi-square test and Logistic regression model.Results (1) Surgical and postoperative situations:1 188 patients underwent successful tension-free repair for inguinal hernia.Eighty-five patients (7.155％,85/1 188) had CPIP,including 76 (8.370％,76/908) undergoing open surgery and 9 (3.214％,9/280) undergoing laparoscopic surgery.(2) Follow-up:1 188 patients were followed up for 12-36 months,with a median time of 19 months.Incidence rates of CPIP with visual analogue score ＞ 3were 11.785％(140/1 188),7.155％(85/1 188),5.808％(69/1 188),3.199％(38/1 188) at 1,3,6 months and 1 year postoperatively.Patients were given individualized and reasonable treatment according to their own conditions and CPIP was relieved after conservative treatment including drug treatment,physiotherapy such as acupuncture,nerve block and psychotherapy.Of 5 patients with CPIP after tension-free repair for inguinal hernia undergoing surgeries,1 was relieved nerve ligation by surgery,3 with mesh related pain were removed meshes,1 was taken the fixed stiches out.They were relieved CPIP after above treatments.During the follow-up,161 patients with incisional seroma,75 with incisional infection and 5 with disruption of wound were cured by symptomatic treatments including reinforced incision management,dressing change and physiotherapy.Seven patients with mesh infection were removed meshes.Of 68 patients with hernia recurrence,53 had reoperation,18 complicated with diseases induced severe increased intra-abdominal pressure were suggested to undergo surgeries after treatment of complications.(3) Influence factors analysis of CPIP:① results of univariate analysis showed that sex,age,bodymass index,surgical method,degree of preoperative pain,intraoperative nerve stretching or injury and incisional infection were related factors affecting CPIP after tension-free repair for inguinal hernia (x2 =21.002,6.715,6.012,8.563,11.887,49.447,10.025,P＜0.05).② Results of multivariate analysis showed that sex,body mass index,surgical method,degree of preoperative pain,intraoperative nerve stretching or injury and incisional infection were independent related factors affecting CPIP after tension-free repair for inguinal hernia (odds ratio =1.267,2.986,1.661,3.208,2.034,1.871,95％ confidence interval:1.042-1.392,1.372-4.901,0.998-2.758,1.933-6.013,1.556-3.118,1.095-3.534,P＜0.05).Conclusions Sex,body mass index,surgical method,degree of preoperative pain,intraoperative nerve stretching or injury and incisional infection are independent related factors affecting CPIP after tension-free repair for inguinal hernia.Preoperative pain management and psychological counseling,intraoperative refine performance,inguinal nerve protection and postoperative incisional management should be reinforced to prevent and reduce incidence of CPIP.