Abstract: T91 steel pipes were joined by transient liquid-phase(TLP) diffution bonding process using FeNiSiB amorphous alloy as filler in argon atmosphere .The influence of the bonding parameters on the microstructures and mechanical properties of bonded joint was investigated by using the orthogonal experiment.The microstructures and properties, as well as the element distribution of the joints were examined.TLP bonding parameter is determined. The testing results showed that the solidified bond were consists of a primary solid solution with a composition similar to that of the parent metal and free from precipitates and proper mechanical properties.The optimum process has been obtained as the following :bonding at 1250℃ for 3 min under 6 MPa with FeNiSiB composite interlayer.