A preparation method of a momordica grosvenori and chrysanthemum tea beverage. Momordica grosvenori has a sweet taste, is cool in property, can dispel internal fire, and has the health-caring functions of clearing heat, detoxifying body, moistening lung, boosting liver, engendering fluid, relieving thirsty, relieving cough, resolving phlegm, moistening intestines and relaxing bowel, and inhibiting asthma when being drunk for a long time; chrysanthemum has the effects of reducing blood pressure, killing cancer cells, enlarging coronary artery and inhibiting bacteria, and can increase calcium in human body, regulate myocardial functions and reduce cholesterol when being drunk for a long time, and is suitable for middle aged and elderly people and prevention of epidemic conjunctivitis; oligosaccharide belongs to prebiotics and can alleviate constipation, prevent and relieve intestinal diseases, balance micro-ecology in intestine, reduce concentration of blood fat, alleviate diseases in nervous system, improve absorption of minerals, enhance immune system, delay senility and improve gastric motility, thereby achieving the effects of detoxifying body and relaxing bowel, clearing fat and nourishing face, maintaining skin health and improving body health. The momordica grosvenori and chrysanthemum tea is a popular health-caring beverage, and has important significances for improving health level of people in our country and preventing diseases.