Abstract: This paper focuses on issues such as the complexity and time-consuming calculation of the pressure at the end of a slender vacuum tube in actual working conditions, as well as the inability to measure the pressure inside the tube. Through three methods including software programming calculation based on theoretical derivation, numerical simulation, and experimental test, the pressure distribution law within the slender vacuum tube is investigated. The results show that the pressure difference between the ends of the slender tube is related to the geometric parameters of the slender tube, and the pressure distribution in the slender vacuum tube presents a typical parabolic distribution characteristic, in which the pressure gradient on the pump port side changes most significantly; the pressure distribution in the tube can be effectively optimized by shortening the length of the tube or increasing the diameter. The results of this research provide a theoretical basis and technical support for the optimal design of the vacuum system and have important engineering application value for improving pumping efficiency, optimizing the vacuum pressure distribution in the slender tube, and ensuring the consistency of the process.