Abstract: In order to calculate the power loss more correctly and to evaluate the performance of the gas transport part in the isotope production equipment, the flow field inside and outside of the gas transport part was studied by using a pressure-correction methods. The distribution of the velocity and the pressure was acquired. It was found that some change was formed in front of the head of the gas transport part, and interacted with the boundary. The total power loss declined 30%~50% when the variable diameter part were employed. The schlieren equipment and PIV were used to measure the shock waves and the vortices around the gas transport part. The experiment was conducted in the high mach wind tunnel FD-03 in China Academy of Aerospace and Aerodynamics. The characteristics of the flow field were obtained, which revealed that the shock wave had a curvilinear structure and did not change significantly when the head of the gas transport part was chamfered. The vorticity was decreased and the vortex was more closed to the boundary. The power loss decreased 15%~20% with the chamfered head. The gas transport part designed (with variable diameter and the chamfered head) satisfied the practical need.