We previous identified the antifibrotic active ingredients from Carapax Trionycis as two peptides. Here, we synthesized these two peptides (peptide 1 and peptide 2) by a solid phase method and examined their effects on proliferation and activation of cultured hepatic stellate cells (HSC) which are the main ECM (extracellular matrix)-producing cells in fibrosis progression. We demonstrated that peptide 1 and peptide 2 significantly reduced HSC proliferation and activation in a dose dependent manner. Further, peptide 1 and peptide 2 could interfere with TGF-signaling by down-regulating Smad 3 phosphorylation. Thus, these synthetic peptides of Carapax Trionycis could inhibit proliferation and activation of HSC and might be used as a candidate for treatment of liver fibrosis.