Effects of respective adding 5, 10, 15, 20 g of Cordyceps militaris culture medium ( named sample 1, sample 2, sample 3, sample 4) into soy sauce fermentation on soy sauce koji-making and activities of protease, amylase, leucine aminopeptidase and cellulase were studied by adopting none Cordyceps militaris culture medium addition as control. The number of spore in mouldstarter was measured using hemocytometer, and sensory changes were observed as well. Results indicated that: 1) In sample 2, the number of spore was the most and appeared vigorous. Plump hypha was overgrown on fluffy basic material and Aspergillus oryzae spores appeared at light yellow at 48 h, mature Aspergillus oryzae spores with yellow-green color sprout from fluffy basic material at 54 h. 2) Activities of protease, amylase, leucine aminopeptidase and cellulase in the process increased at first and then declined after it reached maximum. Activities of enzymes reached their peak at 48 h, while, that of acid protease reached its peak at 42 h. 3) Activities of neutral protease, alkaline protease, acid protease, amylase and cellulase in samples were higher than those in control, and those in sample 2 were significantly higher than those in other samples (P＜0.05), while there was no statistical significance for activity of leucine aminopeptidase between in samples and in control. Therefore, adding Cordyceps militaris culture medium into soy sauce fermentation could improve quality of soy sauce koji and activities of enzymes, and they reached the highest in sample 2. The results could provide a reference for the production of soy sauce with Cordyceps militaris.