Abstract: Abstract: A physical model test was adopted to study the energy performance of an S-shaped shaft-extension tubular pumping system at 5 blade angles (θ=-4°, -2°, 0°, +2°, +4°) by energy tests in the hydrodynamic engineering laboratory of Jiangsu Province, of which total uncertainty is ±0.39%. A signal collecting analyzer EN900 and a vibration velocity transducer VS-080 made by Schenck Process GmbH were used to study the vibration characteristics of model pumping system at blade angle +4° and -4° based on different pumping system operating conditions with the pumping system head range from 0.0 m to 7.0 m at the same rotating speed. Two measuring points P1 and P2 were arranged in the inlet of the guide vane. The X direction indicates the radial direction measured by P1; the Y direction indicates the vertical direction which measured by P2. The test results show that the highest hydraulic efficiency of the pumping system is 83.55% at blade angle -2°, the flow rate is 289.58 L/s and the pumping system head is 4.438 m. Compared with the hydraulic efficiency of traditional shaft tubular pumping system, that of the new S-shaped shaft-extension tubular improves by about 5%. Compared with the highest hydraulic efficiency of hydraulic model TJ04-ZL-23 in the range of blade angle -4°-+4°, the maximum decrease in the maximum efficiency is 5.22% at a blade angle of +4°, and the minimum decrease is 2.47% at a blade angle of +2°. At the same blade angle, the amplitude Ap-p of the X direction is higher than that of the Y direction, but the dominant frequency of both has the same value in any operating conditions. With increasing pumping system head, the amplitude Ap-p of the X direction decreases first then increases. At the same value of pumping system head, the amplitude Ap-p of the X direction at a positive blade angle is higher than that at a negative blade angle. There is little difference between the amplitude Ap-p of the Y direction at different blade angles. The maximum amplitude Ap-p of the X direction is 74.526 μm and that of Y direction is 27.679 μm in different testing conditions, both of which are less than the maximum allowable value (or, alternatively, "tolerance"). The dominant vibration frequency is 22.5Hz for monitoring points P1 and P2 at blade angle +4°, which is the same as rotation frequency, while the dominant vibration frequency is 45 Hz for monitoring points P1 and P2, which is different from both the rotation frequency and the blade frequency. The rotation frequency is the main influence on the frequency of the pumping system vibration at blade angle +4°. An expression was established for the functional relation between the unbalanced vibration frequency and the rotation frequency and blade number. The dominant frequency of unbalanced vibration at monitoring points P1 and P2 is equal to the product of one third of the blade number and the rotating frequency at blade angle +4°, while at blade angle -4° the dominant frequency of unbalanced vibration at monitoring points P1 and P2 is equal to the product of two thirds of the blade number and the rotating frequency. The dominant vibration frequency is therefore a different function of rotation frequency and blade frequency for different blade angles. The study can be a reference for type selection and design of a pumping system.