Abstract: At present, the traditional method of preparing aluminum foam complex forming parts is forming after foaming of the preform. Because the temperature of the preform after foaming decreases, the forming defects will be caused. Firstly, the aluminum foam preform was prepared by friction stir welding with different parameters, then the foaming tests of the preform at 680℃ for different holding time were carried out. The influence of process parameters on the preparation of aluminum foam by friction stir welding was summarized. Thermal tensile tests was carried out for the preform prepared with the best welding parameters to determine the best thermal forming parameters. The results show that the weld spacing of 3 mm, the welding speed of 50 mm/min and the rotational speed of 2000 r/min are the best welding parameters, and the best foaming parameters are 680℃ heat preservation for 110 s. The preform has excellent thermoforming ability and the elongation can reach 46.20%at 450℃ and 2 mm/min thermal stretching. Using friction stir welding to prepare the preform and then hot forming and foaming the preform may be a new way to prepare aluminum foam complex special-shaped parts.