The properties and the measuring method of guanosine enzyme in barley malt were studied in this paper. In the experiment, barley malt powder was homogenized with cold buffer at the ratio of 1 to 5(w/v). Then the supernatant was filtered to obtain the crude enzyme solution. Then enzyme catalytic reaction was in progress for 30 min at 40℃ (0.8 mmol/L guanosine in 9 mmol/L potassium dihydrogen phosphate-dipotassium hydrogen phosphate buffer, and pH6.8) and such reaction was stopped by boiling. And product guanine content was measured by HPLC. The measured guanosine enzyme activity was as high as 5.241 U/mg under the above conditions. RSD of such method was 1.558 %with good re-peatability and high sensitivity. Accordingly, it was suitable for measuring guanosine enzyme activity.%对大麦芽中鸟苷酶的酶学性质及测定方法进行了研究。大麦芽粉与缓冲液以1：5（w/v）比例制备匀浆，过滤后取上清液得到粗酶液；在鸟苷浓度为0.8 mmol/L，磷酸二氢钾-磷酸氢二钾（pH6.8）的浓度为9 mmol/L，反应温度为40℃的条件下，反应30 min，煮沸终止反应，用液相法测定产物鸟嘌呤的含量。在上述条件下，测定鸟苷酶酶活力为5.241 U/g。该方法RSD=1.558%，重复性较好，灵敏度高，可以作为检测鸟苷酶酶活力的方法。
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