Objective To investigate the efficacy of microsurgical subinguinal varicocelectomy for unilateral varicocele.Methods One hundred and five cases with left side varicocele were enrolled from August 2012 to October 2016.Thirty one cases suffered from varicocele in Ⅱ degree,and other seventy four cases in Ⅲ degree.Clinical data including operation time,sperm quality,testosterone level,complications and natural pregnoncy rate were retrospectively analyzed.The measurement data were expressed by (x) ± s.Sperm concentration,sperm motility,the rate of sperm normal morphology and serum testosterone levels were compared before and after operation with paired t test.Results The average operative time of varieocele was (58 ± 9) minutes in the outer ring of the microscope.Compared with preoperation's,sperm concentration,sperm motility,the rate of sperm normal morphology was remarkable improved after 3 month.However,serum testosterone levels were steady.In the outpatient follow-up,there were no complications,such as orchiatrophy,hydrocele of tunica vaginalis or recurrence of varicocele.The rate of natural pregnoncy in one year was 46.7％.Conclusions Microsurgical subinguinal varicocelectomy can remarkably improve sperm quality for patients,who suffer from varicocele in Ⅱ or Ⅲ degree.The complication of microsurgical subinguinal varicocelectomy is rare.Male infertility patients resulted from varicocele will get favorable natural pregnoncy rate.