The invention provides a preparation technology for an aluminum alloy groove piece. The preparation technology solves the problems that an aluminum alloy section bar is little in deformation and low in rejection rate, saves energy, and is environment-friendly in the manufacturing process. The manufacturing process of the aluminum alloy section bar sequentially comprises the following steps that 1) aluminum is smelted and cast into aluminum-cast sticks; 2) squeezing forming is conducted; 3) aging treatment is conducted; 4) cold treatment is conducted. According to the preparation technology of the aluminum alloy groove piece, due to the fact that alloy elements are reasonably optimized and matched, the intensity, the corrosion-resisting performance and weather-proof performance of the aluminum alloy section bar are improved, the stretching-resisting strength at the indoor temperature can be 480-530 MPa, the average grain size can be 0.018-0.035 mm, the rejection rate of the section bar is greatly reduced and the forming of the section bar is stable in the water cooling state by controlling the section bar extrusion speed and extrusion pressure, uniformity of internal structures of aluminum materials and refining of crystalline grains are improved, and the quality and the machining performance of the aluminum alloy section bar are improved.