The present invention relates to a method for fermenting red-ginseng concentrate by using a strain, the method characterized by including the steps of: cryopreserving lactobacillus strains of Lactobacillus acidophilus KCCM 32820, Lactobacillus plantarum KCCM 11322, Bifidobacterium infantis KCCM 11207 for preparation； culturing the lactobacillus strains； firstly culturing the lactobacillus strain statically； secondly culturing the lactobacillus strain statically by using the first cultured strain； thirdly culturing the lactobacillus strain statically by using the second statically cultured strain； mixing the third statically cultured lactobacillus strain with prepared red-ginseng concentrate and then fermenting the resultant. Since the present invention uses various lactobacillus, which inhibit inside of intestine, to ferment red ginseng concentrate, when ingest, types and an amount of saponin which can be absorbed by various digestive enzymes produced by each lactobacillus increase, thereby increasing absorptivity of ginsenoside. As such, the present invention relates to a method for preparing red-ginseng concentrate by using 3 types of lactobacillus derived from the human to maximize an effect of red-ginseng in anyone. [Reference numerals] (AA) First process: a step of preparing a lactobacillus strain and red-ginseng concentrate； (BB) Second process: a step of culturing the lactobacillus strain； (CC) Third process: a step of firstly culturing the lactobacillus strain statically； (DD) Fourth process: a step of secondly culturing the lactobacillus strain statically； (EE) Fifth process: a step of thirdly culturing the lactobacillus strain statically； (FF) Sixth process: a step of fermenting red-ginseng concentrate by using the lactobacillus strain； (GG) Packaging본 발명은 균주를 이용한 홍삼 농축을 발효하는 방법에 관한 것으로서,LactobacillusacidophilusKCCM 32820, LactobacillusplantarumKCCM 11322, BifidobacteriuminfantisKCCM 11207의 유산균 균주를 냉동 보관하는 준비단계, 유산균 균주를 배양하는 단계, 유산균 균주를 1차 정치 배양하는 단계, 상기
