Objective To investigate the presence of apolipoprotein A 1 (APOA1) and its function in human spermatozoa. Methods The expression assays for APOA 1 were carried out by immunofluorescence and Western blotting in human sperm cells . Set up a blank control group , rabbit polyclonal IgG group , which contain anti-APOA1 antibody 10 μg/ml, 20 μg/ml and 40 μg/ml, to treat normal semen samples and incubated at 37 ℃for 1 h, 2 h and 3 h.The progressive motility of spermatozoa was determined bya computer-assisted motion analyzer ( CASA ) , apoptosis rate by flow cytometry and ultrastructural changes by electron microscopy .Comparisons of sperm progressive motility and apoptosis rate were performed by independent sample t tests.Results The study showed APOA1 protein mainly located in the sperm head , the molecular size was 31000.A significant decline in sperm progressive motility was observed after 1,2 and 3 hours of incubation with APOA1 antibody.There was a statistically significant difference between the blank control group and the APOA 1 antibody concentration of 20 μg/ml and 40 μg/ml groups [ 1 hour after incubation , blank control group ( 68.65％ ±15.70％) with 20 μg/ml group (48.45％±5.20％), 40 μg/ml group(39.25％±7.89％), t=2.442, 3.345 , both P<0.05;2 hours after incubation, blank control group(55.33％±10.12％) with 20 μg/ml group(28.68％±11.70％), 40μg/ml group(18.13％ ±10.52％), t=3.445, 5.097,both P<0.05; 3 hours after incubation, blank control group(35.73％±14.08％) with 20μg/ml group(15.53％±8.42％), 40μg/ml group(9.98％± 7.08％), t=2.462, 3.268,both P<0.05].After incubation 2 hours, the percentage of apoptotic cells increased from 16.02％ ±4.28％ in the blank control group to 21.72％ ±2.67％ ( 20 μg/ml APOA1 antibody)and 28.01％±3.93％(40 μg/ml APOA1 antibody), respectively (t=3.177, 5.834, both P<0.01).Treatment with 40 μg/ml APOA1 antibody for 4 hours resulted in major morphological changes to sperm cells observed by electron microscope , including membrane distension ,vacuole formation and different periods of apoptosis cells .Conclusion APOA1 plays an important role in maintaining sperm motility and survival rate,however the mechanism needs further study .