By monitoring the line voltage and current of the driving motor during linear friction welding (LFW) of GH4169superalloy,the frictional power of the rubbing interface between two components to be joined was detected. The data was recorded by a data acquisition card and processed by the LabVIEW software.By analyzing the evolution of frictional power,the joint formation mechanism was discussed.The curves of the measured basic variables (frictional power,axial shortening,interfacial temperature and axial pressure) reflected the characteristics of the LFW process and offered an effective way for welding parameter optimization.