Objective To explore the cause and treatment of chronic pain after tension-free repair of inguinal hernia. Methods 〗The clinical data of 426 cases with inguinal hernia underwent the tension-free hernioplasty during February 2002 to September 2007 were retrospectively analyzed. Results 〗Tension-free hernioplasty was performed to all patients. According to operative methods, they were divided into two groups: polypropylene filling group (n=210) and expanded polytetrafluoroethylene (e-PTFE) mycromesh group (n=216). The chronic pain rate after operation, polypropylene filling group (9.0%, 19/210) was significantly higher than e-PTFE mycromesh group (4.2%, 9/216)， P＜0.05. Conclusion 〗The tension-free repair by e-PTFE mycromesh has less pain in the inguinal hernia due to the material is more suitable to human physiology, more soft and light, with less complications.