Bead-on-plate welds was made by underwater wet welding with flux-cored wire in a tailor-made pentrough. The effect of welding parameters such as welding speeds, welding currents and welding voltages on welds surface appearances and microstructure were studied. Orthogonal experiment method was used to optimize combination of different welding parameters. The results showed that the hardness (HV) of welds fusion zone ranged between 515 and 670 while the hardness (HV) of base metal was only 350. The fusion zone of the welds was mainly composed of columnar grain structure.