Abstract: Q690 steel has a great hardening tendency, high welding crack sensitivity and poor weldability. Q690MD and Q690ME are selected for the test, and GFR-110K3 is selected as the welding material. Four groups of tests are carried out with CO₂ gas shielded welding. The test piece is preheated and interpass temperature is under control in the welding process. 48 hours later, ultrasonic testing and radiographic testing are conducted, then, the tests of tensile, bending, impact, hardness and macroscopic metallographic are carried out after qualified non-destructive testing. The results show that the tensile strength of the welded joint is not less than 781MPa, the low temperature impact toughness KV2≥54J, the Vickers hardness HV10≤321, and the defects such as incomplete penetration, incomplete fusion and cracks are not found in the macro metallography. The selected welding materials and welding process parameters have good matching with the base metal.