The invention discloses an aluminium alloy profile for a building template, and a preparation method thereof. The aluminium alloy profile comprises the following components in percentage by weight: 0.85-0.95 percent of magnesium, 0.06-0.65 percent of silicone, 0.15-0.20 percent of copper, 0.05-0.08 percent of manganese, 0.03-0.05 percent of zirconium, 0.04-0.06 percent of chromium, 0.008-0.012 percent of titanium, 0-0.2 percent of iron, 0-0.10 percent of zinc and the balance of aluminium. The aluminium alloy profile provided by the invention has the advantages that the tensile strength is more than 300 MPa, the yield strength is more than 260 MPa, the breakage elongation percentage is more than 12 percent, the tenacity, the weldability and the corrosion resistance are obviously improved compared with that of an original 6061 alloy, the pendulum impact value is more than 20 J / cm<2>, the welding coefficient is not less than 0.6, smaller quench sensitivity is provided, and critical quenching speed is dropped from 10 DEG C / S of the original alloy to 7 DEG C / S; during the processing of the aluminium alloy profile, air cooling is adopted to process an extrusion outlet with the temperature of 450 DEG C in a high-temperature segment as well as an extrusion outlet with the temperature of being smaller than or equal to 25 DEG C in a low-temperature segment, while a moderate-temperature segment, namely a quench sensitive area with the temperature of 450-250 DEG C utilizes water mist to replace direct water-cooling, so that the difficulty for controlling cross section deformation of the profile in the production field is greatly reduced.