The invention discloses a functional beverage for antagonizing preoperative and postoperative stress reactions, and belongs to the technical field of functional beverages. The functional beverage is prepared through the following steps of performing clarification treatment on hippophae rhamnoides fruit juice to obtain hippophae rhamnoides fruit clear juice; performing clarification treatment on blueberry fruit juice to obtain blueberry fruit clear juice; and compounding the hippophae rhamnoides fruit clear juice, the blueberry fruit clear juice and water, performing uniform mixing, adding D-ascorbic acid, then adding citric acid and sodium citrate, adjusting acid, after acid adjustment, adding white granulated sugar, levulose and glucose, then adding potassium sorbate, finally, adding casein phosphopeptides and other nutrient enrichment agents, and performing uniform mixing to obtain the functional beverage. The beverage can antagonize postoperative stress reactions, increase immune function of patients, stimulate insulin sensibility to reduce postoperative insulin immunity, reduce wound infection, reduce postoperative nausea and vomiting, reduce calming and strong desire to sleep,enable people to be released from the hospital quickly, and reduce other complications during the perioperative period, and is suitable for quick rehabilitation of surgical operation patients.