Abstract: The fully automatic friction eutectic soldering process is studied by using Au80Sn20 eutectic filler metal in this paper. Several important process parameters such as soldering temperature, soldering pressure, friction amplitude, and cycle count are analyzed by orthogonal experimental method, and the influence of process parameters on soldering area ratio is obtained. Meanwhile, the primary and secondary influencing sequences of each process parameter and the optimal combination have been determined. The eutectic soldering experimental verification of GaAs microwave power chips is conducted by using optimized process parameters. Experimental results meet the demands of GJB 548C–2021, indicating that the research methods and conclusions in the paper have certain reference significance for the high-quality eutectic soldering process optimization of microwave power chips.