The invention discloses a thermal treatment device and a thermal treatment technology of an ultra-long aluminum extrusion, and belongs to the technical field of material processing. The thermal treatment device comprises a heating furnace, a quenching water well, a feeding and discharge rail, a feeding trolley, a discharge trolley, a lifting device and a material basket, wherein a furnace body isan ultra-long horizontal furnace composed of a plurality of regions of which the temperature is independently controlled; and a product is horizontally stacked in the material basket, and enters the furnace body or the quenching water well through the feeding trolley, the discharge trolley and the lifting device to be subjected to thermal treatment. According to the thermal treatment device and the thermal treatment technology, horizontal furnace horizontal heating and inclined descend soaking quenching technologies are adopted to replace traditional vertical quenching and roller hearth type quenching technologies, the quenching cooling speed is high and uniform, quenching deformation of the product is low, surface quality is good, and performance is uniform; solid-solution quenching, annealing and ageing functions can be achieved, production scheduling is flexible, length of a biggest product of thermal treatment is large, charge batch is large, production efficiency and heat utilization rate are high, and operation is safe and reliable; and besides, deep well, heat-resistant roller, spraying devices, and the like are not required, basic requirements on equipment are low, and investment is low.