Abstract: The continuous cooling transition curve of 960 MPa grade high strength steel was measured by Gleeble-3800 thermal simulation test machine combined with the structural transformation characteristics and microhardness changes. And Y-groove welding cold crack sensitivity test and welding procedure qualification of the steel were carried out by the argon-rich gas shielded welding procedure. The results show that microstructure transformation of the steel in heat affected zone is as follows,martensite transformation of t_8/5＜ 30 s,mixed transformation of martensite and bainite of 60 s ＜ t_8/5＜ 100 s,bainite transformation of 150 s ＜ t_8/5＜ 600 s,pre-eutectoid ferrite,pearlite and bainite mixed transformation of t_8/5＞ 1 000 s. In the welding process,there is no softening phenomenon in the welded joint of 960 MPa grade high strength steel. As the heat input decreases,t_8/5 decreases,the tensile strength decreases,and the HAZ toughness increases. At the same t_8/5 level,the plate thickness has little effect on tensile strength and HAZ impact energy. For the 960 MPa grade high-strength steel plate with 8 ～ 15 mm thickness,preheating temperature is not lower than 80 ℃ when using 70 kg grade welding wire CHW-70 C,OK13. 29,and preheating temperature is not lower than 100 ℃ when using 90 kg grade welding wire GM120,no cold crack is generated under the above conditions.