The small angle lighting is always a thorny problem in the LED lighting field. The LED lenses and reflectors were important optical devices, which was the key to solve the above problem. So the design of lens and reflectors has been a hot research topic recently. The theory of geometrical optics was used to calculate the coordinates on the lens surface in this paper. Then, the lens model can be constructed based on the coordinates. In order to facilitate understanding, the 30°and 45° lighting lens were taken as examples to introduce the design process. The research findings show that these lenses can concentrate light rays within the predetermined small angles. Furthermore, the efficiency and uniformity are more than 80% and 85% respectively, which can meet the needs of the modern lighting.