The invention discloses a method for simulating the stomach-small intestine-large intestine digestion process of growing pigs and application of the method to estimation of an effective energy value of feed. The method comprises the following steps: crushing and sieving a feed sample; preparing a stomach buffer solution, a small intestine buffer solution, a large intestine buffer solution, simulated gastric juice (containing pepsin), concentrated simulated small intestine juice (containing amylase, trypsin and chymotrypsin) and concentrated simulated large intestine juice (containing amylase, trypsin, chymotrypsin and cellulase); putting the crushed feed sample into a simulated digestive tube of a monogastric animal bionic digestive system, and respectively adding simulated gastric juice in sequence through computer program control to carry out stomach simulated digestion; adding concentrated simulated small intestine liquid for small intestine simulated digestion; adding concentrated simulated large intestine liquid for large intestine simulated digestion; and carrying out cleaning after digestion, and after undigested residues are obtained, measuring the total energy value of the residues and a feed sample, and calculating the effective energy value of the feed. The method overcomes the defect that in the traditional in-vitro simulated digestion method, only cellulase is contained in the large intestine digestion stage, but amylase, trypsin and chymotrypsin with certain active concentration are not contained in the large intestine liquid in the pig body, so that the measured value is closer to the measured values of digestible energy and metabolic energy of an animal test method, the correlation is higher, and the estimation deviation is lower.