In order to increase neutral protease and gluco-amylase activity in soy sauce koji,different carbon source,nitrogen source and inorganic salt were added to koji culture medium and their addition concentrations were optimized.Results indicated that neutral protease activity reached 2 383.83U/g dry matter and gluco-amylase 117.82 U/g dry matter in soy sauce koji cultured in medium with the additions of glucose 0.25%,NaNO3 0.1% and ZnSO4 0.05%,which were increased by 36.75% and 46.02% respectively compared with the control.Furthermore,several indices such as the total nitrogen and amino nitrogen of the optimal group were higher than that of the blank group in low-salt solid-state fermentation of soy sauce.