Abstract: We studied the influence of different shapes and positions of the leading edge and trailing edge and geometric parameters of blades on the internal flow characteristics and energy characteristics of a bulb turbine, and provided a reference for the hydraulic design of bulb turbine blades and other, similar turbines. In this paper, the optimization of the blade was carried out by the use of ANSYS-Bladegen for a model bulb turbine with four blades. The flow field analysis and performance evaluation for a bulb turbine with the initial blade (C-type blade) and the optimized blade (S-type blade) were conducted numerically to reveal the influence that the two blade configurations with different geometric parameters have on the turbine flow characteristics and hydraulic energy performance, especially to analyze the hydraulic losses in each part of flow passage caused by the difference in blade geometry. The results show that for the S-type blade, due to the leading edge and trailing edge of blade are below the C-type's, the consumption location of the velocity moment of the blade in the meridional flow passage is also lower than its need a noun here, and the velocity moment distribution after the runner is also S-shaped. The flow from the guide vanes could be fully developed before entering the runner, which will help reduce the hydraulic losses in the runner. The larger cascade density and blade wrap angle of the C-type blade made the cavitation performance better than the S-type blade, and the area of low pressure on the blade is small, because of the small cascade density and blade wrap angle for the S-type blade, the pressure difference between the pressure side and suction side of the blade is large, so the energy conversion capability is better than the C-type's. The low-pressure region at the outlet of the runner is reduced effectively, which helps to improve the flow characteristics in the draft tube. The leading edge and trailing edge of the blade could play a guidance role to the flow in the flow passage, and this effect is more obvious at low mass flow rate operation conditions. The S-type leading edge shape of the blade could direct the flow to the chamber of the runner, the discharge distribution in the runner shows a similar S-type; S-type runner has small cascade crowding role relative to the C-type, this type of blade could reduce the hydraulic losses in runner, the circulation loss at the outlet of the runner and efficiency loss of the draft tube effectively, and the energy characteristics are superior to the C-type blade.