Abstract: The path placement planning optimization model in coordination welding for arc welding robot system is presented based on RHJD4-1 arc welding robot work cell in this paper.The model is subjected to weld path planning,aimed to minimal movement of positioner and considered the positioner redundant degree of freedom as variable.And then one simulation experiment based on 1200 mm long butt weld seam is conducted.Results show that the optimization model can solve the best path placement planning problem.