Abstract: The curved Fresnel lenses are usually found problematic in application, such as high process complexity, difficulty in surface accuracy control, high production cost and so on. To avoid these problems, based on studies of unequal-thickness slab Fresnel lens design, we propose a slab Fresnel lens design method that employs spherical center lens, inclined outer ring and equal-thickness surface. Specific design examples, as well as their computer optical simulation are given in this paper. Simulation result shows the optical efficiency of the Fresnel lens design achieves 90.7%. This kind of design provides a reference for engineering applications of the Fresnel lens applied in high concentrating photovoltaic modules.