Abstract:The characteristics of electromagnetic design and main structure design for high - altitude bulb tubular - turbine generator of DuoBu hydropower station are introduced. Aiming at the station in high altitude area,the difficult problems,that is, the corona is easily produced and it has difficulty with discharge and heat dissipation,are solved through the electromagnetic optimization design,the corona proof and insulation altitude correction of stator,the pole optimization design of rotor,and selecting appropriate axial fan for ventilation system.