The present invention relates to a method for preparing conventional fermented paste products by cooking soybeans, shaping fermented soybean lumps, and aging the fermented soybean lumps. The method includes: a soybean cooking step of soaking selected soybeans in purified water for 8 to 16 hours at a room temperature and cooking the soybeans for 60 to 90 minutes at 105°C to 110°C a Pueraria lobata extract preparing step of drying and grinding Pueraria lobata washed separately in advance to obtain Pueraria lobata powder while obtaining a hot-water extract and a gherkin extract of Pueraria lobata by extracting the raw flowers of Pueraria lobata with a solvent a conventional fermented soybean lump preparing step of adding a predetermined amount of the Pueraria lobata powder to the cooked soybeans to shape conventional fermented soybean lumps a conventional fermented soybean lump bacteria culturing step of packing the conventional fermented soybean lumps mixed with the Pueraria lobata powder with rice straws and culturing natural bacteria thereon in the air for 40 to 60 days a first aging step of inputting the Pueraria lobata extract to the conventional fermented soybean lumps, mixing the conventional fermented soybean lumps with salt water with a predetermined salinity rate, and putting the conventional fermented soybean lumps into an aging pot to age the conventional fermented soybean lumps a paste separation step of separating the liquid soy sauce and the solid fermented soybean paste from the completely aged and fermented substance and a second aging step of putting the separated liquid soy sauce and solid fermented soybean paste into individual sterilized pots, adding a predetermined amount of the Pueraria lobata extract to each of the pots, blending the mixture therein, and aging the substance in the pots under a predetermined aging temperature condition. The conventional fermented paste products are cultured and aged by using the Pueraria lobata extract. Acc
