In this paper, a method for extracting alliinase from garlic plant was established and the enzymatic characteristics of alliinase were studied. The extracting method was determined by single factor and orthogonal experiments. The results indicated that the best extracting conditions were as follows: solid/liquid ratio 1:3 (g/mL) and extracting 3 times, under which the Vmax and Km were 1.05 μmol/min and 2.38 mmol/L, respectively. The alliinase was constant under the conditions of 30 ℃ and pH 6.88.