The microwave joining of Y-123 superconductors was studied. It was discovered that after joining the joined region became denser and some impurities such as Ｙ2ＢａＣｕＯx,Ｂａ2-yＣｕyＯx and CuO were easyly detected. After post-annealing in air at 960℃ for 15h and cooled to room temperature, Ｙ2ＢａＣｕＯx was obviously diminished, Ｂａ2-yＣｕyＯx almost disappeared completely. And Tc of the joined specimen was 89.7, 1.6K lower than that of the original sample. But during the post-treatment, the superconductor in the joined region was recrystallized, the joined region was widened and the holes were enlarged.