The invention discloses a method for assisting hydrolyzing saponin by microwave radiation, which comprises the following steps of: performing acid adjustment on a plant or an extract thereof which is subdivided and to be hydrolyzed; introducing the plant or the extract thereof into a microwave-assisted hydrolysis tank; heating with steam to raise the temperature, and maintaining the pressure for 10 to 20 minutes; and starting a pulsewidth adjustable microwave generator for microwave radiation to assisting hydrolyzing for 10 to 30 minutes, and fishing the hydrolysis. Compared with the conventional hydrolysis method, the method can greatly shorten the hydrolysis time, reduces acid consumption and energy consumption, has the advantages of complete hydrolysis, high efficiency, and easy treatment for hydrolysis waste liquor, and is new low-carbon and environment-friendly hydrolysis process technology.