In this paper, Friction Stir Welding(FSW) experiments are conducted using similar and dissimilar metals of 6061-T6 Aluminum alloy, AZ-31 Magnesium alloy, JISC-1100 pure copper as specimens. Thermalcouples of type D are used to measure temperature history at different postions of workpiece duing Fsw. Form the temperature history, the preheating temperature and the tool rotation and tool moving speed can be found for a successful welding process. The experimental results show that the temperature ranges for the tool starting to move after preheating are 250-2500C, 200-2500C and 300-3500C for silimar metals of Al alloy, Mg alloy and pure copper and that for of dissimilar of Al alloy and Mg alloy is 200-2500C. Vickers hardness test and tensile test of the welded products are also conducted. The hardness testing results show that the vickers hardness of similar Al alloy, Mg alloy and pure copper sheets beforing weldig are about, 102, 70 and 105HV, respectively. The hardness of the nugget region of similar Al alloy, Mg alloy and pure copper sheets after welding are about 60, 62 and 65 HV, respectively and that for dissimilar of Al alloy and Mg alloy sheets is 138HV. The tensile testing results shows that for similar of Al alloy, Mg alloy and pure copper sheets beforing weldig are about, 320, 300 and 280MPa, respectively. The tensile strenghts of similar Al alloy, Mg alloy and pure copper sheets after welding, are about 160, 250 and 200 MPa, respectively, and that for dissimilar Al and Mg alloys is 100 MPa. The above experimental results can provide information for Fsw of Al, Mg alloys and pure copper. Keywords¡GFriction Stir Welding¡Fthermalcouple¡Ftemperature career