The invention discloses a walnut diaphragma juglandis phenolic extract, which is characterized in that the content of flavone in the phenolic extract is 64.5-66.1%, the walnut diaphragma juglandis phenolic extract has the effect of preventing abnormal glucose and lipid metabolism, and the phenolic extract is obtained by pretreatment, extraction, separation, concentration, drying and determination. The walnut diaphragma juglandis phenol low-dose extract and the walnut diaphragma juglandis phenol high-dose extract can remarkably inhibit impairment of oral glucose tolerance of a model animal with abnormal glucose and lipid metabolism, remarkably reduce the damage degree of OGTT, remarkably inhibit increase of AUC, glycated serum protein GSP, fasting blood glucose FBG, fasting insulin FINS, insulin resistance index HOMA-IR and insulin sensitivity index ISI, and can be used for preparing the medicine for treating the abnormal glucose and lipid metabolism. The rise of serum total triglyceride TG, total cholesterol TC and low-density lipoprotein cholesterol LDL-C level and the reduction of the low-density lipoprotein cholesterol HDL-C level of a model animal with abnormal glucose and lipid metabolism are obviously inhibited. The walnut diaphragma juglandis phenol extract is high in flavone content and can be used as a food or feed additive and a human or animal medicine raw material.