This study aims to produce an interactive multimedia development product based on adobe flash geometry introduction material in grade I Elementary School that is valid and practical. This type of research is development research or research and development. This study uses the Plomp development model (2013) which consists of 3 development stages including the Preliminary Research Phase, Prototyping Phase, and Assessment Phase. The research data were collected by means of observation, interviews and questionnaires. The data is then processed through quantitative and qualitative analysis techniques. Based on the validation results of interactive multimedia based on Adobe Flash that was developed, the Aiken's V validity index was 0.88 with a very valid category. While the practicality of interactive multimedia based on Adobe Flash based on the teacher's practicality questionnaire, it was obtained an average score of 92.02% in the very practical category. In addition, based on the students' practicality questionnaire, the average percentage score of 89.35% was obtained in the very practical category. Based on the results of this study, it can be concluded that interactive multimedia based on Adobe Flash has met the criteria of validity and practicality so that this product can be used by teachers and students in learning geometry introduction in grade I elementary school.