Abstract: A high precision equivalent experimental method for measuring micro-zone tensile properties of 6061-T6 aluminum alloy MIG welded joint was established. The temperature changed during the welding process was simulated by finite element, and relationship between temperature and tensile properties of joint micro-zone was established. The parameters that could characterize properties of each micro-zone material of joint was obtained, and verified that joint was equivalent to materials in different thermal states to established the fine model for predicting the properties of joint was reliability. The results show that the simulation of the temperature field, weld pool morphology and tensile properties were in good agreement with the experimental results. The error of the peak force between simulation by eguivalent weld joint and experiment was only 0.1%, and the displacement error of fracture failure was only 5.7%. The heat affected zone grid was divided into different thermal state materials on the basis of temperature distribution could effectively predict tensile properties of weld joint.