Radioluminescent nuclear battery is a type of energy conversion device that can be miniaturized, which has the ability to convert nuclear energy into light energy, and again into electrical energy. To explore the response relationship between the phosphor layer structure and the electrical performance of radioluminescent nuclear battery, the physical model was established to research the deposition energy distribution by using Monte Carlo method. The radioluminescence spectra and current-voltage characteristic curves were used to investigate the optical and electrical properties. Through a comprehensive comparison of single plane layer, double plane layer, and V groove layer structures, the simulated results are consistent with experimental results. The results indicate that the Monte Carlo simulation is applicable to analysis of the phosphor layer structure of radioluminescent nuclear battery. Additionally, the results also show that the structure type and physical parameters of the phosphor layer have great influence on the energy deposition. A suitable phosphor layer structure can provide a new route to exhibit higher energy conversion efficiency as well as improving the matching degree between the range of radioactive particles and the thickness of the phosphor layer.