The invention discloses a pulmonary artery valve replacement device and a support thereof. The support comprises a valve fixing part, the top edge of the valve fixing part and a support part used for supporting a left pulmonary artery or / and right pulmonary artery are connected through a transitional section, and both the valve fixing part and the support part are of cylindrical structures. The transitional section is provided with a transitional arc surface fittingly contacting with the inner wall of blood vessels. The pulmonary artery valve replacement device comprises a pulmonary artery valve support, an artificial valve is arranged in the valve fixing part, and the valve fixing part is provided with a tectorial membrane below the artificial valve. The pulmonary artery valve support and the pulmonary artery valve replacement device can solve two problems that backflow of pulmonary artery valve and restenosis of pulmonary artery after pulmonary artery valve operation at the same time and are high in stability, operation risk of support displacement is avoided, damage of blood vessels are less prone to causing, stenosis of pulmonary artery branches is solved and repeated implanting of multiple supports is not needed.