The technical characteristics of the offshore plant construction welding field are mainly composed of multi-layer welding of the parts having improved shape due to limitation of heat welding on the heavy plate compared to the shipbuilding industry. It is a very big problem to secure or nurture them, and efforts are being made to automate or mechanize them. In this paper, we will develop a robotic teaching algorithm for direct teaching that is necessary to develop portable welding robot based on high power density module of direct teaching method.