Abstract: Weldability of high strength low alloy steel plate of continuously cast 10CrNi3MoV with different carbon-content is investigated adopting strength-matching wire 10MnNi2MoTi and fused flux 705-ch in different welding heat input and temperature.The welding joint exhibits good mechanical properties and fabrication weldability, but the toughness of the joint decreases in high heat input (～40kJ/cm). To improve the HAZ toughness, the heat input should be controlled no higher than 40kJ/cm and the carbon content of 10CrNi3MoV steel should be controlled within a narrow range for the sake of the toughness of 10CrNi3MoV steel plate.