In order to inspect the anti‐diabetes effect of the polysaccharide extracted from Dendrobium officinale leaf named LDOP‐A, the present work first investigated the structure and simulated digestion of LDOP‐A in vitro and then explored secretion of GLP‐1 from endocrine L cells in vitro under the direct stimulation of digested LDOP‐A. This evidence concerns the gene GCG and diabetes mellitus.