Pigs are currently considered the most likely source of organs for human xenotransplantation because of anatomical and physiological similarities to humans, and the relative ease to be bred in large numbers. Along with the fast development of the genetic engineering and organ transplant immunity medical science, the research of liver xenotransplantation suffers the very big valuing in recent years. Whether the livers from different species after transplanting can perform the normal function, depends on the function regeneration and lucid rates of hepatic portal vein. The objective of this study was to investigate the age effect on biomechanical properties of pig hepatic portal vein to pave the way for seeking a reliable biomaterial for future pig-to-human liver xenotransplantation. Methods: The biomechanical remodelling of the hepatic portal vein of pigs for 1,2,3,4,5 and 6 months (n = 6 per month) were measured in this study. The blood vessel was given periodic permanent loading and unloading, and repeated force-deformation data were obtained. The incremental modulus ( Einc), the longitudinal incremental modulus ( Ep), the circumferential incremental modulus ( Ev), incremental compliance (C) and wall thickness were calculated based on the recorded pressure–diameter curves from experimental data. Results: The incremental modulus, pressure strain modulus and the volume modulus of the pig hepatic portal vein increases with the age increased (P < 0.01), while the compliance decreased with the increasing of the age (P < 0.01). Conclusions: Our present study suggests that the biomechanical properties of the pig hepatic portal vein are age dependent, the pig hepatic portal vein with biomechanical properties that match those of human hepatic portal vein should be chosen for liver xenotransplantation. [ABSTRACT FROM AUTHOR]