Abstract: To study the potential application value of Ary-Ary-Leu(RRL) specially combined with tumor derived endothelial cells in tumor molecular imaging for melanoma bearing mice, a novel peptide RRL was designed and labeled with ¹³¹I by chloramine-T method, and mice bearing melanoma tumor were injected ¹³¹I-RRL to imaging. The labeling results showed that the optimized condition were following: 50 μg RRL, 10 μL（74 MBq）Na¹³¹I, 90 μg chloramine-T, total reaction volume 100 μL, and reaction time 3 min, the labeling yield was over 69%. The labeling compound was purified by Sephadex G25, its radiochemical purity was ＞95%. In vitro binding experiments, FITC-RRL was mainly combine with tumor cells and tumor angiogenesis endothelial cells, and in the SPECT imaging, ¹³¹I-RRL peptide could successfully image the tumor in nude mice bearing melanoma tumor for 24 h after injection. The results indicated that small molecular peptide RRL was a promising carrier for tumor molecular imaging and radioimmunotherapy.