A new welding method of bi-friction stirring welding has been proposed. Microstructure and hardness of 6K32-T4 aluminum alloy joint in friction stirring welding （FSW） and in bi-friction stirring welding （Bi-FSW） have been compared

meanwhile the joint in Bi-FSW has been observed by XRD. The results show that microstructure distribution of the joint in Bi-FSW is identified with that of in FSW. However

the hardness in Bi-FSW is slightly lower than that in FSW

in which the declined area of the hardness in bi-FSW is larger than that of in FSW. Change of the phase constituent of the joint after bi-FSW is not observed. Using bi-FSW instead of FSW is beneficial to improving the welding efficiency and to eliminating tunnel-like joint defects due to higher linear energy

improving properties of the joint.