Thermal simulation and arc welding were carried out to test the weldability of atmospheric corrosion resistant steel 07MnCuPTiNb. In thermal simulation experiment, welding thermal cycles with different peak temperature and different cooling rate were adopted and the microstructure and impact toughness were analyzed. In arc welding experiment, different heat input was used and the microstructure, impact toughness, hardness distribution, tensile strength and bending ductility of welded joints were examined. When small heat input is used for welding, the impact toughness of HAZ remains to be good. The broken position of tensile test specimen is located in base metal zone. The joint also has good ductility.