Investigating the process of evacuating people from a space such as a stadium, theater, or classroom is very interesting not only for managers and relief organizations but also for designers and researchers in the field of architecture. In this study, the evacuation process of a classroom with 42 students in emergencies was investigated by computer-based simulation using the A* algorithm and the impact of three architectural variables including doors width, the number of exit doors and orientation of the class were compared with each other in twelve different scenarios. The results of this study showed that the greatest effect on decreasing evacuation time was related to the number of exit doors and the least effect was related to the class orientation. Further investigations revealed that the orientation of the classes had effected on decreasing the evacuation time when the density of the front doors was reduced by using the other architectural variables.