The invention discloses two tripeptides of ground beetle extract and their preparation method, pain-easing effect and use in quality standard setting. The two tripeptides comprise tripeptides Pro-Ala-Arg and Val-Ala-Arg and the tripeptides Pro-Ala-Arg and Val-Ala-Arg exist in ground beetle dry-powder zymolyte or water extract and have the highest content. The invention provides the preparation method of the tripeptides and the pain-easing effect of the tripeptides and further discloses the use of the tripeptides in setting of quality standards of ground beetle dry-powder zymolyte or water extract.