By using MAG welding with φ（Ar）80%+φ（CO,2,）20% shielded gas,the welding procedure test of 8 mm thick TS980QC steel plate is carried out to study the cold crack resistance sensitivity of material,the influence of welding heat input on welding quality and the comprehensive quality of welded joint. The results show that the cold crack in the welding of TS980QC high-strength steel（8 mm thick） can be avoided at a preheating temperature over 50 ℃. This steel is sensitive to welding heat input,and its performance decreases when the heat input is too high or too low. The welding wire selected in the experiment can match the performance of TS980QC high strength steel when using the appropriate technological conditions.