The emergency scenarios of passenger ships are reproduced unrealistically by evacuation drills due to cost and safety limitations, and model simulation is an effective alternative method. To study the evacuation efficiency of an inclined ship, a deck of a Ro-Ro ship with 1065 passengers was modeled on a simulation platform developed based on a social force model (SFM). A series of inclined scenarios were produced by adding the walking speed attenuation factor to the individual parameters. Furthermore, the influence of crew’s guidance was considered in this model, and the effects on evacuation were also analyzed for the entire deck. The simulation results show that the larger the inclination angle is, the more evacuation time that is needed. When the largest inclination angle was 20°, the evacuation time increased by 32.6%. In addition, the participation of crew’s guidance in all of these scenarios significantly accelerated the evacuation efficiency, and this benefit was achieved by the evaluation of the exit flow and congestion level by crew. However, organizing orderly evacuations as soon as possible when the inclination angle is less than 15° and making maximum efforts to ensure evacuation success are still recommended. The findings provide useful insights into a large group of Ro-Ro passenger vessels under inclined emergency evacuation.