The invention relates to the technical field of aluminium product processing, in particular to an anti-corrosion aluminium bar and a preparation method thereof. The anti-corrosion aluminium bar comprises the following processing raw materials: 1.5%-3.3% of Mg, 1.2%-1.5% of Si, 1.0%-1.7% of Cu, 0.04%-0.08% of Fe, 0.07%-0.14% of Zn, 0.4%-0.8% of Mn, 0.4%-0.8% of Ni, 0.03%-0.06% of Ti, 0.05-0.09% ofCr, 0.02%-0.04% of Mo, 0.01%-0.03% of Ba, and the balance of Al. In the processing process, small calcium-magnesium alloys as anodes with the same shapes are separately connected to two ends of a molded aluminium bar, so that the aluminium bar is taken as a cathode; and in the storing process of the aluminium bar, the calcium-magnesium alloys of which the chemical property is higher than that of aluminium are subjected to chemical corrosion first and play a chemical protecting role in sacrificing an anode and protecting the cathode, so that the corrosion of the aluminium bar in the storing process is effectively prevented, the use value of the aluminium bar is increased, and the service life of the aluminium bar is prolonged.