Modules are printed teaching materials that are designed to be studied independently and have a systematic structure containing learning materials, learning activities and evaluation tools to achieve the expected competencies. The results of the 1st year development research a multi-representation-based physics module to improve students' critical thinking skills that meet validity and practicality. Multirepresentation is the presentation of the same material in different forms of delivery, which can be in verbal, mathematical, pictorial and graphic forms. The purpose of this study is to describe practicality including the implementation of learning, student activities, obstacles that arise. In addition, effectiveness includes critical thinking skills and student responses to the application of the module. The type of research used is Research and Development (R & D). The development model design used is the development model by Thiagarajan, namely the 4-D development model, which consists of four stages of Define, Design, Develop, and Disseminate. The research was carried out in the Even Semester of the 2022/2023 Academic Year on the work and energy. Extensive trials or dissemination were carried out at high schools in the former Besuki residency with research subjects involving 35 class X high school students. Collecting data in a study, namely questionnaires, interviews, observations or observations, tests and documentation. Critical thinking indicators include interpretation, analysis, evaluation, inference, explanation, and self regulation. Seeing the importance of this, multi-representation-based physics modules still require an implementation test by conveying concepts and implementing steps as teaching materials that explain one unit in a coherent and precise manner. Therefore, there is a need for further research on implementation to describe practicality including the implementation of learning, student activities, the obstacles that arise. In addition, effectiveness includes critical thinking skills and student responses to the application of multi-representation-based physics modules.