Objective To investigate the changes of the mechaniccal properties of hepatic portal vein in the pig with various ages and to provide mechanical data for pig-to-human liver xenotransplantation.Methods The hepatic portal vein of different ages of pig were used to conduct mechanical experiment, and the data of Pressure and Diameter was measuted to calculate the elastic modulus and compliance.Results The elastic modulus of hepatic portal vein of pig incresaed with aging and pressute in vessel, while the compliance descended with aging.Conclusion The mechanical properties of hepatic portal vein of pig change with aging, the pig matched the mechanical property of hepatic portal vein of human should be chosen for liver xenotransplantation.