The subject invention aims to solve the problem of production of glucose accompanying the production of galactooligosaccharides after milk raw material is treated with lactase, by additionally adding transglucosidase to convert glucose to functional isomalto-oligosaccharide. The subject invention relates to a process for the production of a milk product enhanced with oligo-saccharides, characterized in that lactase and transglucosidase are used to treat milk raw materials. The subject invention further relates to the milk product of the process of the invention, whose oligo-saccharide content reaches a functional level. Human physiological effect assays confirm that the milk product increases intestinal probiotics, reduces harmful intestinal bacteria, improves the intestinal bacterial flora, reduces blood total cholesterol, reduces blood LDL cholesterol, increases blood HDL cholesterol, and improves the immunity, and may be used as low glycemic index (GI) dietary supplements.