Alpha amylase, beta amylase and limit dextrinase are the main enzymes of starch hydrolysis in malt, it’s content and proportion affect the sugar spectrum of wort, and then influence the fermenting performance of yeast and beer quality . The article analyses the malt amylase activity from different areas (Canadian and Australian) and varieties (Metcalfe、Copeland、Hind marsh、Bass、Baudin、Scope、Gairdner) , it was found that the amylase activity of Canadian malt is generally higher than Australian malt and there were great differences in different varieties,. By analysis the relationship between amylase activity and it’s conventional indicators, the result shows that there is a strong correlation between the diastatic power and beta amylase and limit dextrinase . Then blend the barley malt according to different enzyme activity, the change of enzyme activity before and after mixing was analyzed, found after mixing three enzymes activity of malt are higher than the theoretical values calculated in proportion, the result indicates that malt collocation can bring synergistic effect. In order to further study the amylase activity has effect on the wort sugar, the wort was prepared by the Saccharification process that containing auxiliary material (rice), the relationship between amylase activity and the sugar composition of mixed malt’s wort was analyzed, we found that the key enzyme affecting limit attenuation and the ratio of fermentable sugars in wort is the limit dextrinase. This study provided a theoretical basis for the raw material prescription, the addition of enzymes and consistence of wort components.