A STEM methods course was developed for undergraduate preservice teachers at the faculty of education. The course model design had three phases: 1) review of the STEM literature and conceptual considerations, 2) planning of the STEM methods course, and 3) evaluation by experts and revision based on their feedback. Research literature and other documentation were reviewed. A framework and guiding principles for primary-level STEM education were developed to identify key elements, including STEM focus/essence, student-centered, curriculum, learning environment, and assessment. A 15-week STEM methods course was planned to model good practices for teaching integrated STEM and to let preservice teachers confront real-world issues and problems that arise in STEM instruction and then design their own STEM lessons or activities for teaching. The result of implementing the STEM methods course was examined through pre and post-surveys which showed the influence of the methods course in promoting preservice teachers' STEM understanding.