The development of E-book teaching materials for heat and displacement based on dynamic multi-representation has been carried out to improve students critical thinking skills. The development was carried out using the ADDIE model with the One Group Pretest-Posttest experimental design method. The problem discussed in this case is how effective the E-book teaching material is heat and displacement based on dynamic multirepresentation to improve students critical thinking skills. The research was conducted in class VII E of SMPN 10 Jember for the 2022/2023 academic year, which consisted of 32 students. Data was collected using pretest and posttest questions. The effectiveness of the E-book is measured through the pretest and posttest given to students and analyzed using the n-gain test. The results showed an increase in pretest and posttest scores and an n-gain of 0.65. Due to the acquisition of 0.3 ≤ g < 0.7, it can be concluded that the E-book teaching material based on dynamic multi-representation heat and displacement is effective in improving students critical thinking skills with moderate improvement categories.