This paper performs the result of effects on submerged-arc welding modes (including three parameters: amperage welding, voltage welding U and velocity welding V) to the strength of butted plate in steel ship. Through the strength testing of specimens according to the rule TCVN 6259-6:2010, the 21 experiment specimens conducted by submerged-arc welding with some different modes, it concludes that the welding mode (amperage welding I = 1000(A), voltage welding U = 35(V) and velocity welding V = 27(m/h)) is the best.