T91/12Cr2MoWVTiB was bonded by transient liquid phase bonding process with different pressures, one commercial FeNiCrSiB was used as the interlayer. The microstructure and components distribution of the bonded joints were examined by optical microscope and scanning electron microscopic techniques. Furthermore, the properties of the joints were also tested. The results indicate that with the increase of the pressure – from 2 MPa to 6 MPa – the microstructures and mechanical properties were improved, and more similar to those base alloys. A theoretical study also revealed that the isothermal solidification complication time can be shorter, because the maximum liquid width was reduced with the existence of pressure.