Project-based learning is one of the most effective and successful teaching methods for STEM topics. Project-based teaching is an open-ended teaching method that helps teachers stimulate students' initiative and teamwork skills and promote creativity. Of the interdisciplinary STEM topics, teaching students how to produce aromatic wax proved an interesting topic, causing excitement to students. Through collaborative teaching, this research has shown that students are very interested in learning to produce aromatic wax. The research results also show that there are five factors that greatly affect project-based teaching: (1) Teachers must split the class into groups to implement projects effectively; (2) Topics must be attractive and motivate students to appreciate, explore and produce STEM products; (3) Students must have a positive attitude, unafraid of encountering difficulties and challenges in completing STEM tasks; (4) Students must be competent to implement STEM products; (5) Students must be facilitated by their school and their parents to complete the STEM tasks. The research findings have important implications for proposing a specific project-based learning curriculum on the STEM topic of aromatic wax production.