It has been reported that the photopolymer solidification in the stereolithogrpahy process is mainly depend on the laser exposure conditions such as laser power and scanning speed. However, these researches were focused on the vertical laser exposure onto the surface of the photopolymer. In this research, we developed a mathematical model for the photopolymer solidification under the inclined laser beam exposure. Using the developed mathematical model, the photopolymer solidifications were simulated varying inclined laser exposure conditions. Developed mathematical model was in good agreement with the experimental result. This research can be applied to improve the surface roughness in the stereolithogrpahy process.