Abstract: The current research aimed to develop design thinking mindset and knowledge related to biomimicry and its applications among pre-service science teachers during field training through a proposed program on biomimicry and its applications in science education, based on Biomimicry Design Model, and Measuring its effectiveness in developing sustainable thinking skills among preparatory school students while teaching a science unit for first-year preparatory students in the first semester of the 2024/2025 academic year. Accordingly, a research sample of 85 third-year students from the Faculty of Education, Zagazig University, specializing in Biology, Chemistry, and Physics, was selected, along with a sample of 68 first-year preparatory school students, who were divided into an experimental group and a control group. The research tools included a Design Thinking Mindset Scale, a knowledge related to biomimicry and its applications Test, and a Sustainable Thinking Skills Test. The study adopted a quasi-experimental design, using a one-group pre-post test design for pre-service science teachers and a two-group pre-post test design for preparatory school students. The results indicated a statistically significant improvement (at the 0.01 level) in the post-test performance of the research group students compared to their pre-test performance in terms of developing design thinking mindset and knowledge related to biomimicry and its applications. Additionally, the results showed that the experimental group students outperformed both their pre-test scores and the control group students with a statistically significant difference (at the 0.01 level) in developing their sustainable thinking skills.