Five commercialized proteases are used to hydrolyze porcine liver. Experiments are performed using various enzyme/protein ratios. Results show that the higher the enzyme/protein ratio, the higher the degree of hydrolysis. In general, the rate of hydrolysis reaction becomes sluggish after 2 hours. Experimental results show that the digestibility of these proteases are in the descending order of Alcalase, Trypsin, Papain, Pepsin, and Asp. oryzae-protease. Hydrolysates are then analyzed to exa mine the contents of protein, lipid, amino acids, carbohydrates, ash and water. The sprayed-dried supernatants of products contain 56.62~65.61% protein, while the precipitates of hydrolysates contain 38.20~59.50% protein. The amounts of essential amino acids do not change during hydrolysis. However, the ash contents of hydrolyzed products increase, because of the neutralization of pH with acid or alkaline. Therefore, further desalting process may be required.