This study aims to improve the mental model of prospective primary school teacher related to the concept of boiling through the implementation of the conceptual development-oriented instruction (CDOI) model assisted by multimode visualization. This research was conducted using the pre-experimental method with the design of one group pretest-posttest. The subjects of the study were 36 the prospective primary school teachers, consisting of 20 female and 16 males. The research location is one of the universities in Riau province. The instrument used for collecting data is the conceptual understanding level test related to the concept of boiling in the form of open-ended that cover three parts of the question, which has previously been validated and tested for its reliability. The results of this study indicate that the implementation of the CDOI model assisted by multimode visualization has high effectiveness in facilitating the achievement of the scientific mental model, and no gender bias on achieving scientific mental models by the prospective primary school teacher.