Luminescent solar concentrator (LSC) photovoltaic system can cut down the cost of photovoltaic electricity generation by reducing the consumption of solar cells. Compared with the single-layer LSC, the cascaded LSC can make use of the solar spectrum effectively and obtain high photoelectric conversion efficiency. In this paper, the physical processes of the single-layer and cascaded LSC are analyzed and the corresponding mathematical models are established. Based on the models, the simulation software is developed to calculate the photoelectric conversion efficiencies of the LSC and the cascaded LSC. The effects of the size of the optical waveguide and the bandgap of solar cells on the total conversion efficiency are investigated.