Welding is crucial and huge technology in engineering science. Especially in manufacturing engineering it is the basic element to manufacture quality product. But there are different factors (welding variables) which barriers from achieving quality product. Those factors apply their influence on the microstructure, the metallurgical property, the chemical composition and mechanical property of the welding structure and weldments. This leads to the failurity of many structures, industrial construction, structural members of building and bridges, vessels of welded plate construction and the failurity of these members and structures bring hazard on human beings and their property. This is the reason why this research wants to analysis the effects of welding parameters on mechanical properties of SMAW on S355JR structural mild steel.