The invention discloses a health food capable of replenishing amino acids and enhancing immunity and a preparation method thereof. The health food includes the following components, by weight, 10 to 15 parts of poria cocos extracts, 10 to 20 parts of yam rhizome extracts, 2 to 10 parts of L-valine, 2 to 10 parts of L-leucine, 2 to 10 parts of L-isoleucine, 2 to 10 parts of L-threonine, 2 to 10 parts of L- phenylalanine, 2 to 10 parts of L-methionine, 2 to 10 parts of L- tryptophan, 2 to 10 parts of L-lysine monohydrochloride, 2 to 10 parts of L-histidine hydrochloride and 2 to 10 parts of orange powder. The health food has the characteristics of high absorbability, high utilization, high biological activity and high safety, and is low in cost, easy to digest and of no toxic and side effects. The health food specially aims at meeting the requirement of children, the traditional Chinese medicine theory and the modern nutriology are combined and comprehensiveness, science, economy, safety and the like are taken into considerations so that the health function of enhancing immunity can be well performed.