The purpose of the present research paper is to examine the effect of advertising rhetoric on advertising persuasion process and explore the role of mental imagery and style of processing. Experiments were conducted involving a sample of 360 Tunisian students who were exposed to six advertising posters: for every rhetorical poster we made another different one which has not rhetoric content. Structural equations modeling were used by applying the maximum of likelihood method. Results highlight the moderator effect of style of processing as well as the significant effect of the interaction between the advertising rhetoric and mental imagery. A cluster and a discriminant analysis helped us better know about the specificities of our sample: three groups were identified. They are different depending on the level of their mental imagery. The effect on advertising persuasion process differs from one group to another.