There are many hazards on a ship that makes an emergency evacuation process inevitable. Providing safe and effective evacuation of passengers from ships in an emergency situation becomes critical. Handling a real ship evacuation practice is often unaffordable as modelling such an environment is very expensive and may cause severe distress to participants. As an alternative, simulation models have been used to overwhelm the issue above in recent years. Therefore, this paper proposes a novel simulation-based methodology for evaluating the effect of factors including physical as well as psychological passenger characteristics and routeing systematic on emergency evacuation process for public marine transportation. A detailed questionnaire has been conducted in this work to reflect passenger characteristics on simulation model in a more realistic manner. Also, a new routeing systematic is developed to provide an efficient evacuation procedure. As another contribution, a novel grid-based approach where the meshed discretized nodes can contain more than one passenger is proposed in simulation model for the first time. Then, a statistical analysis is included within the methodology to assess the importance level of each factor on evacuation time. The proposed methodology is applied to a real life Ro-Ro ferry. A validation protocol based on IMO regulations is conducted and confirmed the effectiveness of the suggested simulation model. The simulation of different scenario types have indicated the influencing factors in a ship emergency evacuation. According to results, passenger characteristics has been identified as the most dominant factor on evacuation performance. The highest evacuation time difference has been observed for different levels of weight attribute. Moreover, it is concluded that the consideration of load utilization balancing among evacuation systems for routeing decreases evacuation time significantly. Finally, significant evacuation time difference between grid approaches have been demonstrated.