Abstract: As China’s economy is developing and upgrading rapidly, pumped storage technology becomes increasingly important in China’s power-supply system and to China’s policy of enhancing the exploitation of renewable energy. The construction of pumped storage projects (PSP) in China has experienced a rapid development stage and will gradually enter a faster developing stage. Therefore, various issues of power unit vibrations found in the operation of commissioned projects, have attracted great attention of the research community. Using the statistics of the number of runner blades in combination with the number of wicket gates and an analysis on specific cases, this paper presents a detailed explanation for the major causes of unit vibrations such as rotor-stator interaction and phase resonance, and suggests that the scientific research concentrate on the dynamic design of power units and particularly on two blade-gate number combinations of 7/20 and 9/20 and their mechanism of hydraulic excitation. In sight of the vibration problems found in various PSPs at a head range around 300 m, we recommend to focus on the field measurement of prototype vibrations and hydraulic pulsations, and to actively carry out experimental and theoretical studies on the dynamic mechanism. Such research will not only solve the existing vibration problems in the built projects, promote their safe and reliable operation, and prolong their service lives, but also make positive and important senses of ensuring the safe construction of numerous ongoing and future PSP projects.