Abstract:The effects of air plasma on temperature，pH value，cell survival rate，extracellular protein and extracellular nucleic acid content of yeast 3G-28 were studied.The experimental results showed that after 5 min of treatment，the survival rate of yeast cells was 29.797%and the growth of bacterial colonies was not affected by the increase of temperature of bacterial solution and the decrease of pH value. Meanwhile，the extracellular protein content increased by 1.5 times compared with the initial value，and the extracellular nucleic acid content increased by about 2 times. It is concluded that the reactive oxygen species produced by air plasma during the experiment was the main cause of the damage and death of yeast 3G-28 cells.