The bonds of T2 copper/50steel were studied by inertial radial friction welding techniques at different conditions. Ultrasonic C-scan testing was employed to evaluate the bonding situation. In order to verify the reliability of ultrasonic C-scan testing results, the optical microscope, SEM and shear test were used to analyse the microstructure and mechanical properties. It was found that ultrasonic C-scan testing was useful to evaluate the inertial radial friction welding joint situations by analyzing the ratio of good bonded area in the bond area of ultrasonic C-scan images. And the correctness of ultrasonic C-scan testing was testified by microstructure examination. Furthermore, it was concluded that enough metalline plastic deformation occurred, oxide film of joint was destroyed and constituent elements were mutually diffused sufficiently, when two stage pressure was employed and friction pressure 78 MPa, friction speed 3200r/min were used.