The present invention provides a use of total glucosides of paeony in the preparation of a potentiating agent for an immunological checkpoint inhibitor for tumor treatment, wherein the immunological checkpoint inhibitor is a PD-1/L1 inhibitor, and wherein the total glucosides of paeony include albiflorin and paeoniflorin. The present invention also provides a method for tumor treatment, comprising using total glucosides of paeony as a potentiating agent for an immunological checkpoint inhibitor, wherein the total glucosides of paeony enhances an efficacy of the immunological checkpoint inhibitor by improving intestinal flora balance of a cancer patient by means of stress resistance, wherein improving intestinal flora balance involves increasing amounts of gut probiotic bacteria, such as Akk bacteria, ruminococci, lactic acid bacteria, bifidobacteria, Bifidobacterium longum, etc.