The invention relates to a precision casting method for refining aluminum alloy by using an adjustable traveling wave magnetic field, belonging to the technical field of casting. The invention aims to solve the technical problems of high cost and difficulty in control in the process of grain refining and compacting for changing the properties of aluminum alloy in the prior art. The method provided by the invention comprises the following steps: 1. heating to melt aluminum alloy, and carrying out heat preservation,, thus obtaining an aluminum alloy molten mass; and 2. putting a casting mold, which is made of a non-magnetic material, in a traveling wave magnetic field inductor, turning on the traveling wave magnetic field inductor, adjusting the magnetic field intensity of the traveling wave magnetic field inductor, injecting the aluminum alloy molten mass obtained in the step 1 into the casting mold, and applying a traveling wave magnetic field, of which the magnetic field direction is vertically downward and the magnetic induction intensity is 32-500mT, onto the aluminum alloy molten mass to solidify the aluminum alloy under the traveling wave magnetic field, thereby completing the precision casting of the aluminum alloy. The method provided by the invention is easy to control and low in cost; and by utilizing the method provided by the invention, the obtained alloy crystal grains are fine, bubbles and voids can be effectively reduced, and the metal feeding capacity in the solidification process can be enhanced.