Abstract: Potato residue was employed as raw material,and Brewer's yeast,Baker's yeast and Aspergillus niger were chosen to be the starting strains.The aim of this paper was to study the effect of raw material sterilized or not,strain compatibility and proportion on the true protein content,acid protease activity and cellulose activity of fermentation products by solid- state fermentation. The results showed that under raw material without sterilization condition,the compatibility of Aspergillus niger and Brewer 's yeast with ratio of 1 ∶ 1 was the optimal strain combination.The true protein content of fermentation product could reached 17.87%,which was increased by171.17% compared with that before fermentation.Acid protease activity and cellulose activity reached 1187.93 U / g and 61.77 U / g,respectively. So it was feasible to use the potato residue to produce protein feed with a certain biological activity.