Abstract: Tumor is hazard to human health and lives. Early diagnosis and treatment of tumor can obviously prolong patient survival time and improve the quality of life. At present, targeting diagnosis and therapy catch attention of researchers from all over the world. Peptide arginine-arginine-leucine(RRL)sequence is specific targeted to tumor-derived endothelial cell. Our team confirmed that the ¹³¹I-RRL had the effect of killing tumor cells, and ⁹⁹Tc^m-RRL could image tumors in different tumor models. Foreign scholars have already put the small molecules arginine-arginine-leucine targeting tumor angiogenesis in the preclinical stage.