Abstract: According to the nucleate mechanics of acicular ferrite and bainite in high strength low alloy steels(HSLA) welded deposit,Mn-Ni-Mo-Cr was chosen as main alloy elements and Ce,Ti,B as micro-alloy elements which accelerate the nucleate of acicular ferrite.The content of C,Si,P,S,N elements was reduced and C to be the level of ultra-low carbon to meet the large energy input welding,and to ensure the content of Mn,Mo,Cr to compensate for intensity loss brought by reduced C,Si.By in addition,Ti and B were added to avoid producing excessive acicular ferrite which would reduce the intensity or cause segregation of alloy elements to decrease the toughness of weld joint and proper Cu to enhance the ability of weld joint to resist the atmospheric corrosion.As the results,the developed welding wire matching flux SJ101-G,had the microstructure of deposited metal was acicular ferrite and lath bainite mainly in which a small amount of granular bainite precipitated and dispersed.