Abstract: The welding temperature field in twin-wire SAW of E36 steel was analyzed by MSC.Marc.Effects of twin-wire space and welding speed on the welding temperature field were analyzed systematically.The effect of twin-wire space on the molten pool shape and the width of high temperature zone in HAZ were investigated.The results showed that when the heat input was set,and the speed was up to 120 cm/min,the molten pools of the two wires 50 mm apart separated at lower welding speed were joined into one;with welding speed getting higher and space between the two wires bigger,the molten pool became shallower and narrower,and the high temperature zone of HAZ became narrower,which could result in the forming of ridge,so heat input should be adjusted to improve the situation.