The invention relates to a method for extracting pseudoginsenoside RT5 and medical application, which belong to the field of medicaments. The method comprises the following steps of: after total saponins of American ginseng are added into macroporous resin, eluting by using water and 25 to 45 percent ethanol in turn till saponins are not reacted; continuously eluting by using 35 to 55 percent ethanol; collecting eluent; recycling a solvent; drying by distillation; and recrystallizing to obtain the pseudoginsenoside RT5. The pseudoginsenoside RT5 is applied to the preparation of anti-myocardial ischemia medicaments.