A dynamic parameters model is presented based on cellular automata for pedestrian evacuation in this paper. The dynamic parameters: Direction-parameter, Empty-parameter and Cognition-parameter are formulated to simplify tactically the decision-making process of pedestrians, which can reflect the pedestrian judgment on the surrounding conditions and decide the pedestrian’s choice of action. Pedestrian moving rules were established, according to two-dimensional cellular automaton. The simulation results of the model are analyzed. It is observed that there is a linear relationship between evacuation time and pedestrian density, however, there is a negative exponential relationship between evacuation time and exit width. The simulation results correspond with the actual, it is instructional significant for pedestrian evacuation.