The finite element analysis simulation software ANSYS was used to simulate a 2219 aluminum alloy friction stir welding process.The temperatures at different time and different positions were presented to make sure how the temperature is distributed in the space-time temperature field in steady-state phase.The results indicate that the maximum welding temperature is 525 ℃, lower than the melting point of aluminum alloy.In an experiment, adopting the welding parameters which were used in the simulation, the quality of weld surface is well.The error of temperature on the work piece, compared with the result of the simulation, is less than 5 percent.In a mechanical performance testing, a specimen by FSW (friction stir welding) is obviously better than those by other welding processes.Its tensile strength reaches 74% of that of the base metal.In an actual welding process, when a 2219 aluminum alloy plate with 6 mm thickness was welded, the welding parameters have been refered to those used in the simulation and good results were achieved.