Abstract: The brazing connection between AlN ceramics and Cu was achieved by using Cu-Sn-Ti filler metal, and the effect of process parameters on the interfacial microstructure and properties of AlN/Cu joints was investigated. Brazing was conducted in a high-temperature vacuum furnace. The melting temperature range of the filler metal was determined based on the DSC curves. The interfacial morphology, element distribution, and phase composition of the joints were observed by means of SEM and EDS. The results indicate that the interfacial microstructure of the joints is AlN/TiN + TiCu/Ti₂Cu + Ti₂Sn + Cu(s,s)/Cu. As the brazing temperature increases, or the holding time is prolonged, the thickness of the intermetallic compound layer Ti₂Sn phase in the brazing seam zone gradually decreases, while the thickness of the interfacial reaction layer TiN near the AlN side gradually increases, and its distribution state transforms from discontinuous to continuous. At a brazing temperature of 900 ℃ and a holding time of 10 min, the shear strength of the joints reaches a maximum of 40.77 MPa. The fracture location shifts from the brazing seam interface to the AlN ceramic side and finally within the AlN ceramics. The thermal diffusivity of the joints exhibits a trend of initially increasing and then decreasing with the increase of brazing temperature or the prolongation of holding time and reaches a maximum of 61.33 mm²/s at a brazing temperature of 900 ℃ and a holding time of 10 min.