The invention provides nutrient solution with the advantages of rich nutrition, easy absorption and comprehensive effects. The nutrient solution is prepared from astragalus, chinaroot greenbrier rhizome, peanut kernel, Chinese data and medlar serving as raw materials. A method for preparing the nutrient solution comprises the following steps of: after cleaning the raw materials, cutting the astragalus and crushing the rest components; adding water, mixing and boiling for 20 to 30 minutes; and filtering to obtain the nutrient solution, and sterilizing and preserving. The nutrient solution after being taken for a long time has the effects of adjusting physique, obviously improving and enhancing the immunity of patients with tumor, increasing leukocytes, inducing interferons, conditioning body functions, enhancing detoxifying and detoxicating capability, and has the advantages of scientific compatibility and rich nutrition. The nutrient solution well keeps nutritional ingredients by adopting ultrahigh temperature (UHT) instantaneous sterilization, and has the advantages of low cost, simple and easy preparation method, and obvious economic and social benefits.