Illumination system is an important component of projection display system, and decides the whole brightness and uniformity of the whole system. Fly-eye system is a commonly used illumination configuration in liquid crystal display (LCD) projectors. In traditional fly-eye illumination systems, the elemental lens of fly-eye always has the same aspect ratio as the LCD device. But when applied to wide screen projection systems, this will lead to a certain energy loss. This paper presents a new method for improving the performance of wide screen projection display illumination systems, which introduces cylinder lenses. Results of simulation show that a total increment of about 5% to 10% of the output lumens is available with this improved fly-eye system.