This article used the active metal method to seal nonoxide ceramics-nonoxide ceramics of the same composition (Si3N4-Si3N4, AlN-AlN, SiC-SiC) and nonoxide ceramics-metal material of different composition (Si3N4-4J29, Si3N4-304 stainless steel, Si3N4-oxygen free copper, SiC-4J29, SiC-304 stainless steel, SiC-oxygen free copper, AlN-4J29, AlN-304 stainless steel, AlN-oxygen free copper) in a vacuum welding furnace. The sealing strength of the samples was tested, and the morphology and elemental composition of the sealing interface were tested using SEM and EDS. The results show that the active metal method can be applied to the sealing of Si3N4- Si3N4, AlN-AlN, SiC-SiC, Si3N4-4J29, Si3N4-304 stainless steel, Si3N4-oxygen free copper, AlN-304 stainless steel, SiC-304 stainless steel, and SiC-oxygen free copper. Among them, the SiC-SiC sealing strength is the highest in the nonoxide ceramics-nonoxide ceramics sealing sample, reaching 129.4 MPa. The sealing strength of Si3N4-304 stainless steel (101.9 MPa), SiC-304 stainless steel (135.7 MPa), and AlN-304 stainless steel (79.1 MPa) in the nonoxide ceramics-metal material sealing samples are the higher. The core mechanism of the active metal method is that Ti in the solder migrates at the sealing temperature, with a portion diffusing from the center of the solder to the ceramics interface and forming TiN, TiC and other compounds with elements such as N and C, thus forming a relatively dense interface layer. There is also a small amount diffusing from the center of the solder to the metal, undergoing a solid fusion reaction with the metal, forming intermetallic compounds, and achieving high-strength sealing between heterogeneous materials.