Abstract: Objective To synthesize peptide RGDSY-CTTHWGFTLC (RGDSY-CTT), which derived from peptide CTTHWGFTLC (CTT), to improve its water-solubility and stability, and antitumor efficacy. Methods (1)Peptide RGDSY-CTT was designed and chemically synthesised. CTT (positive control ) and STT (STTHWGFTLS, negative control ) were synthesised and analyzed by mass spectrometry. (2)Type Ⅳ collagenase, casein were mixed up with peptides RGDSY-CTT and CTT respectively, and then incubated for 1 h at 37℃. The degradation of casein was analyzed by SDS gelelectrophoresis. (3)RGDSY-CTT and CTT were dissolved in distilled water to detect quantity of protein by BCA quantitative assay. (4)MCF-7 cells were incubated with peptides RGDSY-CTT, CTT and STT respectively in 96-well polystyrene plates precoated with fi bronectin (10 μg/ml) for 2 h. The effects of oligopeptide on adhesion of MCF-7 cells were detected in cell adhesion tests. (5)MCF-7 cells were incubated with peptides RGDSY-CTT, CTT and STT respectively in Transwell membrane. The effects of RGDSY-CTT and CTT on the migration of MCF-7 cells were detected by cell migration test. Results Peptides were synthesised and analyzed by mass spectrometry, which accorded with expectant. RGDSY-CTT and CTT could restrain the hydrolization of casein, which was induced by MMP-2 and MMP-9. The inhibition ratio of RGDSY-CTT at 250 μg/ml was 53.6% and CTT was 77.7%. While the concentration reached 500 μg /ml, the inhibition ratio of RGDSY-CTT and CTT was 94.6% and 96.9%.The maximum solubility of CTT was about 745 μg/ml by BCA test. However, the solubility of RGDSY-CTT was over 4 030 μg/ml. The solution didn't reach saturation.At concentrations of 50, 100 and 200 μg/ml of RGDSY-CTT, the adhesion ratio of MCF-7 cells were 85.1%, 74.1% and 63.8%, which was signifi cantly lower than CTT group(P<0.01).At the concentration of 100 μg/ml, the inhibition ratio of cellular migration treated with RGDSY-CTT and CTT were 42.9% and 39.2%, respectively. At the concentration of 200 μg/ml, the inhibition ratio was increased to 60.8% and 57.0%. Under both concentrations, the inhibition of RGDSY-CTT was both higher than that of CTT (P<0.05). Conclusion The water-solubility of the new peptide RGDSY-CTT is obviously higher than that of CTT.Compared with CTT, RGDSY-CTT could inhibit the adhesion of MCF-7 cells and has stronger migration inhibitory ability.