Microwave joining developed rapidly in recent years, because of its advantages such as 1)low energy consnmption; 2)rapid heating rate; 3)high quality joint. Microwave joining of the Bi-based 2223 superconductor was studied with the results showing, after joining at 900-1000℃ for 10 minutes and post treatment at 855℃ for 60 hours, Tc restored to 107 K, the same as that of the original sample. Electron probe technique was used to study the microstructure features before and after joining.