Abstract:1060 pure aluminum and TC4 alloy sheets with a thickness of 0.2 mm were micro resistance spot welded successfully. The effects of the welding current, welding time and electrode force on mechanical properties of the joints were studied. The joining feature and fracture behavior of the joints were analyzed by using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Also, the phase compositions of the joints were measured by using micro-X-ray diffraction (micro-XRD). The result shows that: with increasing the welding current, the tensile shear load of the joints increases first and then is steady when the welding current is in the range of 0.3~0.7 kA. However, the welding time has no significant effect on the tensile shear load of the joints when the welding time changes in the range of 2~6 cyc. The tensile shear load of the joints presents an increased first and then decreased trend with increasing of the electrode force in the range of 40~280 N. When the welding current is 0.7 kA, the welding time is 3 cyc and the electrode force is 160 N, the maximum tensile shear load of the joints reaches to 91 N, and the fracture occurs in the heat affected zone. A complete nugget is formed, and the interface on the TC4 side is relatively flat while it is unsmooth on the 1060 side. Inside the nugget, lots of Al3Ti, Al2Ti and AlTi3 compounds are generated. And some needle-like Al3Ti compounds are found at the interface of the 1060, which plays an important role in the strength of the joints.