The invention discloses a nickel-base superalloy welding wire for 700 DEG C-above ultra-supercritical coal power generation equipment, and belongs to the technical field of nickel-base superalloys. The nickel-base superalloy welding wire comprises the following chemical components: 0.005-0.08 wt% of C, 22-25 wt% of Cr, 12-22 wt% of Co, 0.5-2.0 wt% of Ti, 1.0-2.5 wt% of Al, 0.5-2.0 wt% of Nb, 0.5-4.5 wt% of Mo, 0.1-3.0 wt% of W, 0.01-0.3 wt% of V, 0.001-0.05 wt% of Zr, no more than 0.02 wt% of Mg, 0.001-0.006 wt% of B, no more than 1.5 wt% of Fe, and the balance Ni and inevitable impurity elements. As such elements as Co, Cr, Mo, W, Al, Ti and Nb and proper amounts of other microelements are added in a nickel-base alloy, the cold/hot machinability, the high-temperature strength and in particular the high-temperature durability of the alloy welding wire are all improved. The alloy welding wire is better in high-temperature strength and durability, and is more excellent in welding process performance; and in the welding process, a molten pool is better in fluidity, and the welding line formability is excellent.