Abstract: Aiming at improving the interfacial bonding quality of friction pull plug welding (FPPW) joints for 2219 aluminum alloy, the evolutions of temperature, plastic strain, and normal stress field during forming of joints were investigated on the basis of both experimental and simulation results, as well as their influence on interfacial bonding quality. The results indicate that during the welding process, when the rotating plug rotates and feeds, the interfacial temperature increases to about 525 ℃, and the material around the interface experiences severe plastic deformation. It can be analyzed that the interfacial normal stress shows non-uniformity throughout the thickness of the plate, exhibiting an initial increase followed by a subsequent decrease. When the plug stops rotating, the interfacial temperature decreases and plastic strain shows no obvious increase. The normal stress at the upper interface increases and exceeds that at the lower interface. It can be analyzed that the normal stress shows more obvious effect on the interfacial bonding quality compared with temperature and plastic strain. By adjusting the volume of plastic flow material near the interface, the normal stress increases and exhibits uniform, resulting in more fresh metal being extruded into the broken area of oxide film, and increasing the real contact area of fresh metal. The interfacial bonding quality and tensile properties of joints can be effectively improved.