Objective To study the relation between function of sperm membrane and seminal parameters.Methods Five hundred and three semen samples were collected from 149 normal men and 354 infertile men.Sperm concentration,motility,viability,semen WBC concentration,morphology and sperm tail hypo-osmotic swelling(HOS) were analyzed according to WHO criteria. Results Sperm HOS score in infertile group was lower than that in control group(P