The invention relates to a manufacturing method for an aluminum alloy extrusion bar. The manufacturing method includes the steps of alloy burdening, alloy smelting, shearing of a casting bar obtained through a low-temperature pouring technology, homogenizing annealing, bar casting, die and extrusion barrel heating, extrusion production, heat treatment and the like. According to the manufacturing method, the casting bar which is uniform in ingredient and good in structure property can be obtained under the combined action of low overheating pouring, chilling at the initial solidification period and mixed stirring, the aluminum alloy extrusion bar can obtain the better comprehensive mechanical property, the strength of extension of the aluminum alloy extrusion bar can reach 605 MPa or above, the stipulated non-proportional extending stress can reach 557 MPa or above, and the after-breakage ductility can reach 10% or above.