The article introduced the selection and verification of the structural pattern of the penstock and spiral case of the TGP power-station. The decisions on the key technical issues in the construction of the TGP were made based on a huge number of scientific tests and verifications. The selection of the structural pattern of the penstock and spiral case in the TGP power-station is not only an important technical and economic issue, but also an issue relating to the long-term operation of the power-station.