To evaluate the efficacy of laparoscopic percutaneous extraperitoneal closure (LPEC) for unilateral inguinal hernia in children and effect of intraoperative laparoscopic exploration for finding contralateral patent processus vaginalis (CPPV) on prevention of the metachronous contralateral hernia (MCH). We retrospectively analyzed unilateral inguinal hernia ligation in children, which can be diveded into two groups: a total of 252 cases with open surgical ligation from January 2010 to December 2012 (open group), a total of 184 cases underwent laparoscopic percutaneous peritoneal hernia sac high ligation LPEC from January 2013 to March 2015 (LPEC group). Then, we observed postoperative complications, recurrence of hernia, and the postoperative MCH in the two groups and analyzed the influence factors of the MCH. In Open groups and LPEC groups, the complication incidences, respectively, were 4.4 and 1.6 per cent, having statistical difference (P > 0.05), the average postoperative follow-up duration, respectively, were 42 months and 22 months, whereas the overall incidence of MCH, respectively, were 5.2 and 0.5 per cent (P < 0.05). In the first 24 months follow-up time, the overall incidence of MCH, respectively, were 3.6 and 0 per cent. Laparoscopic evaluation was positive for CPPV in 67 cases. We found the prevalence of 56.1 per cent of CPPV in LPEC groups aged 0.6 to 2 years old, finding the incidence gradually decline with the increase of age, until 14.3 per cent to 10 to 12 years old group. Our study shows LPEC has proven efficacy in treatment of unilateral inguinal hernia in children, and routine laparoscopic exploration with this simple maneuver should be actively performed to observe CPPV in all chidren.