The invention relates to a reinforcing steel bar and a processing method thereof, in particular to a high-strength reinforcing steel bar with spiral fins and a processing method of the high-strength reinforcing steel bar. The high-strength reinforcing steel bar consists of following components including, in weight percentage, from 0.25 to 0.4% of C, from 0.1 to 0.2% of Si, from 0.3 to 0.45% of Mn, from 0.04 to 0.05% of Nb, from 0.08 to 0.09% of Cr, from 0.01 to 0.04% of V, from 0.002 to 0.003% of B, from 0.001 to 0.003% of Mo, from 0.015 to 0.03 of Al, from 0.002 to 0.003% of S, from 0.008 to0.009% of Ti, from 0.004 to 0.005% of Ni, from 3 to 5% of composite rear earth and the balance Fe. The processing method includes using a roll to roll a reinforcing steel bar into a reinforcing steelbar with the continuous spiral fins on the surface in a hot state; feeding the reinforcing steel bar with the continuous spiral fins on the surface after hot rolling into a heating furnace and heating the reinforcing steel bar to the temperature of 880-990 DEG C; then fast cooling the reinforcing steel bar to the temperature of 650-680 DEG C by an online cooling device via compressed air or vaporous quenching liquid; quenching in a quenching device by water or quenching liquid for 15-25 seconds; and tempering after heating the reinforcing steel bar to the temperature of 500-550 DEG C via a tempering heating furnace. The high-strength reinforcing steel bar with the spiral fins has a good anchoring property, fine ductility and a high yielding-to-tensile ratio.