The mechanical properties, microstructure, fracture morphology and second phase particles of T6 state SiCp/AlMMCs were analyzed by using self-made TiB2 in situ reinforcement and 4047 welding wire as filling materials for TIG welding of T6 state SiCp/AlMMCs. The results show that the weld forming of the two kinds of welding wires is excellent, and the 4047 welding wire is more beautiful, and the tensile strength of TiB₂ joint is obviously better than that of ER4047 joint, and the average strength is 171.88 MPA, which is 40.03% higher than that of 4047 joint. TIB₂ particles play an in-situ strengthening role. The hardness values of the two joints are approximately symmetrical in the center of the weld, and the hardness of the weld zone is the lowest, the average value is 71.65HV,60.02HV. the "overaging" phenomenon of the hardness in the heat affected zone is obvious, the SiC particles in the weld are less, there is a serious barren zone, and no obvious Al₄C₃ brittleness is found. The microstructure is dendritic structure, but the dendritic grain of 4047 joint is coarse, the grain size of TiB₂ joint is fine, the rare earth element Sc,Ce,Be plays the role of refining grain, and the TiB₂ particles are evenly distributed in the weld, and the pores in the fracture surface of TiB₂ joint are few, which is tough. The brittle mixed fracture shows that there are more particles in the second phase in the dimple, and there are more pores in the fracture surface of the 4047 joint, which is ductile fracture, and the second phase particles in the dimple are less.