Okara is a byproduct of soymilk and tofu manufacturing, the high water content make okara spoiled easily and the waste treatment always is a problem of such manufacturer. The purpose of this experiment was to increasing the nattokinase activity of the okara natto by adding different concentrations of xylose or sucrose (0~4%), yeast extract or soy protein isolate (0~10%), sodium chloride, potassium chloride or calcium chloride (0~1.5%) and vitamins mixture (0~1.5%). The results found the nattokinase activity of okara-natto decreased when the concentrations of xylose and sucrose increased. Nattokinase activity of okara-natto increased when the concentrations of yeast extract and soy protein isolate increased. When 1.5% vitamins mixture was added, nattokinase activity of okara-natto increased significantly. The other additives effect had no significantly different effects.