Objective To observe the effects of connective tissue growth factor peptide (P1c)on the thrombus formation by venoarterial bypass in rats. Methods The thrombosis model was established by venoarterial bypass. P1c was injected by the femoral vein of rats at the dose of 2，4，and 8 mg/kg, respectively. Results The groups of middle and high dose of P1c, as well as Aspirin groups, could significantly inhibit the thrombosis formation compared with the blank group (P<0.05). The inhibited rate of thrombosis.formatiom was a linear positive correlation with the dose of P1c. Conclusion P1c possessed the characteristic of anti-thrombosis.formatiom.