The invention relates to a method for improving the banded structure of a 42CrMoA crankshaft, which comprises the following steps of: cogging and forging a hot-fed steel ingot into an intermediate billet through an oil press, returning to a furnace, heating to 1230-1270 DEG C, preserving heat for 10-20 hours, pulling out a trolley, airing the material to 600-650 DEG C, reducing the furnace temperature to 930-970 DEG C, returning to the furnace, preserving heat for 2 hours, discharging, airing the material to 750-800 DEG C, forging and forming by a precision forging machine, quickly cooling the forged piece to 350-400 DEG C after forging, heating to 600-650 DEG C at full power, preserving heat for 1 hour / 100mm, and cooling to the room temperature to obtain the 42CrMoA crankshaft banded structure. The temperature is increased to 840-880 DEG C with full power, heat preservation is conducted for 1-2 h / 100 mm, the temperature is rapidly cooled to 400-450 DEG C after heat preservation is finished, the temperature is increased to 630-670 DEG C with full power, heat preservation is conducted for 4 h / 100 mm, furnace cooling is conducted to the temperature smaller than or equal to 450 DEG C at the speed smaller than or equal to 30 DEG C / h after heat preservation is finished, and the 42CrMoA crankshaft is taken out of a furnace and subjected to air cooling. The problem of the banded structure of a forged 42CrMoA crankshaft is well solved, and the banded structure requirement of the 42CrMoA crankshaft material is met.