The koji-making conditions of Aspergillus oryzae cultivated with whole wheat were optimized and the effects of wheat roasting time,initial moisture content of the koji,inoculum size,culture time and addition of nutrition on protease activity were studied.The results showed that the optimum koji-making conditions were as follows:wheat roasted for 30 min,initial moisture content 55%,inoculum size 0.055%,culture time 46 h,and glucose 3%.Under above conditons,the neutral protease activity of wheat koji was 1424 U/g,equal to that of soybean koji.The acid protease activity was 486 U/g,62% higher than that of soybean koji.