The invention belongs to the technical field of natural product preparation and particularly relates to a method for preparing high-activity corn antihypertensive peptide and a special device. An enzyme membrane reactor comprises a reaction tank, a temperature control system, an automatic pH dripping instrument, a strong force stirrer, a material liquid storage tank, a peristaltic pump, a control valve, a pressure meter, an ultrafiltration membrane assembly, a pipeline heat exchanger, a collection tank, a liquid level controller, a nanofiltration membrane assembly and the like. The process method comprises the following steps that corn gluten meal is subjected to alcohol alkali liquid extraction to obtain concentrated corn protein, the concentrated corn protein is pretreated at high temperature and is then added into a continuous enzyme membrane reactor system, the corn antihypertensive peptide is prepared by adopting the enzyme membrane coupling technology, then, the products are subjected to ultrafiltration grading through the ultrafiltration membrane assembly and then are subjected to desalting through the nanofiltration membrane, and the high-activity corn antihypertensive peptide is obtained. The inhibitory activity of the obtained corn antihypertensive peptide on angiotensin-converting enzyme (ACE) is maintained at a value higher than 86 percent, the protein recovery rate reaches higher than 70 percent, and in addition, the systolic pressure of spontaneously hypertensive rats can be obviously reduced.