The invention discloses an argon arc welding wire for G115 heat resistant steel and belongs to the technical field of welding materials. The argon arc welding wire comprises the components, by weight, of 0.07%-0.09% of C, 0.3% or the less of Si, 0.7% or the less of Mn, 0.002% or the less of P, 0.001% or the less of S, 8.5%-9.5% of Cr, 2.8%-3.3% of W, 2.8%-3.5% of Co, 0.04%-0.08% of Nb, 0.18%-0.25% of V, 0%-0.5% of Cu, 0.007%-0.008% of N, 0.011%-0.014% of B, 0%-0.001% of Ti and the balance Fe and inevitable impurity elements. By means of the combined action of the elements, welding cladding metal components not only have chemical components similar to a base material but also have excellent physical and mechanical properties and good impact toughness matched with the base material; the welding process property is good, spatter is low at the time of welding, metal mobility of a welding seam is good, and the forming property of the welding seam is good; the welding wire is suitable for submerged-arc welding of G115 heat resistant steel.