This paper aims to establish evaluation categories in explanatory presentation assessment in order to contribute developing an education program to improve speech skills for college students. For this purpose an experiment was conducted: 165 students were asked to deliver a presentation and their presentations were assessed by fellow students. The results of this study can be summarized as follows: (1) Factor analysis extracted three factors(organization of the content, expression style and regard to audience) for presentation evaluation. (2) The internal consistency for presentation evaluation was high(Cronbach α = .880) and Cronbach αfor each 3 subtests ranged from .671 to .801. (3) The assessment items of expression style were weighted to two times based on the result of multiple regression analysis.