The invention relates to the technical field of mixed air exhaust systems, in particular to an ultra-compact and high-mixing-efficiency air exhaust system structure adopting a de-swirl lobe mixer. The ultra-compact and high-mixing-efficiency air exhaust system structure adopting the de-swirl lobe mixer is especially suitable for a high-performance aviation gas turbine fan engine. The ultra-compact and high-mixing-efficiency air exhaust system structure adopting the de-swirl lobe mixer comprises the de-swirl lobe mixer with an inlet flow angle, a central cone with a bump and a mixing spray tube; a plurality of wing type reinforcing rib connecting structures are arranged between the de-swirl lobe mixer and the central cone; the lower ends of wing type reinforcing ribs are fixedly connected to the central cone with the bump; the upper ends of the wing type reinforcing ribs are fixedly connected to a de-swirl lobe trough; a trough lobe is a specially-shaped blade structure; the specially-shaped blade has an inlet flow angle; the side wall of the lobe mixer is subjected to concave sector cutting processing; and distances between the front edges of the lower ends of the reinforcing ribs to bump slope of the central cone are 0-3 times chord length of the reinforcing ribs. The ultra-compact and high-mixing-efficiency air exhaust system structure adopting the de-swirl lobe mixer has a plurality of advantages of being high in mixing efficiency, strong in pre-whirling resistance, compact in structure, high in reliability, low in processing and maintaining cost, and the like.