GH3039 has been extensively used in aeronautic industries. Poor machinability and low material usage are common in GH3039 components, which could be resolved by frabricated by additive manufacturing. In this study, a GH3039 thin wall part was fabricated by gas metal arc welding wire arc additive manufacturing (GMAW-WAAM). Optical microscope (OM) observation, microhardness indentation and tensile tests were applied to investigate the microstructure and mechanical properties of the part. Result shows that the defect-free dense part is mainly consisted of interlayer fine grain and coarse column grain, which grew vertically. The ambient temperature ultimate tensile strength (UTS) and fracture elongation (El) of the as deposited part are 520~540MPa and 36~40%, respectively. The elevated temperature (800°C) UTS and El along the deposition direction is 189MPa and 35.4%, respectively. This study verified the feasibility of manufacturing GH3039 part by GMAW-WAAM.