The effect of ethanol concentration,extraction temperature,extraction time and ratio of material to liquid on the extraction amount of thiosulfinates were studied with the thiosulfinates extracted by ethanol solution in garlic.The optimal process conditions were obtained by regression analysis of response surface methodology.The results showed that the optimal extraction conditions were as follows: ethanol concentration 65%,extraction temperature 20℃,extraction time 1.5h and material – liquid ratio 1∶ 4.48(g∶ mL).The extraction mount of thiosulfinates was 4.17mmol/100g.Stability of thiosulfinates was studied and the results showed that the stability of thiosulfinates decreased with temperature increased.During the storage of the extraction liquid,the contents of diallyl disulfide(DADS) and diallyl trisulfide(DATS) increased with the decreasing content of thiosulfinates.