Resistance spot welding (RSW) was applied to non-combustible magnesium alloy, AX41 (Mg-4%Al-1%Ca) to investigate its weldability. The similar material joint of AX41 and dissimilar materials joint between AX41 and aluminum alloy, AA6061 were welded. Tensile shear test was carried out to evaluate joining strength in the similar and dissimilar materials RSW joints. In case of similar material joints, the maximum load obtained with tensile shear test in AX41 similar material joint was higher than that obtained in AA6061 similar material joint. Moreover, higher maximum load was obtained in a similar material joint without surface polishing compared to joint welded with surface polishing in AX41. In case of the dissimilar materials joint, the maximum load obtained was almost comparable with AX41 similar material joint, however scatter in joint strength was large. Weldability of the dissimilar materials joint became poor by applying surface polishing.