In this study, AA 4000 series Al-Si alloys sheets were joined by TIG welding method using alternative and pulsed current. Tensile test, bending test, hardness test and microstructure examination of joined test specimens were carried out in order to see the effect of current type on mechanical properties of welded samples. Experimental results showed that, pulsed current leads to low heat input, grain refinement and hardness increase in weld metal compared to alternative current were used. Specimens joined by the pulsed current showed higher tensile strength than the specimens welded by the alternative current. After bending test, cracks, tearing and surface defection were not observed on the samples.