This study examined undergraduate students' Problem-Solving ability development by employing the Problem-Based-Learning (PBL), the core educational method of STEM when students worked on the design for disaster project at National Taiwan Normal University. The participants were 20 undergraduate students from the second year of Product Design major at the design department. This study investigates how students can develop critical thinking abilities when facing learning challenges, and it aims to establish an educational framework with interdisciplinary knowledge input. The documented students' project developments and the end-of-semester feedback questionnaire emphasize the successful implementation of the STEM method for developing students' critical thinking and problem-solving ability. The study also discusses the importance of integrating STEM education in the design industry for establishing new STEM Literacy.