Abstract: Staphylococcus aureus was one of the most dangerous pathogenic bacterias for causing food poisoning.Food safety problems caused by staphylococcus aureus had been paid more and more attention in recent years.The stability of IgY against staphylococcus aureus was investigated.The IgY had excellent thermal stability and certain endurance to acid and alkali.IgY showed great resistance to pepsin but sensitivity to trypsin.The activity of IgY was not affected by freeze-thawing, but it would reduce after the treatment of freeze dying.Both test in vitro bacteriostasis and double immunodiffusion test showed the antibacterial activity of IgY to staphylococcus aureus.It was expected to substitute antibiotics in the treatment of bacterial infectious diseases.